KAZUYUKI MATSUBAYASHI
| Department of Engineering Science | Professor |
| Cluster III (Fundamental Science and Engineering) | Professor |
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- Mar. 2024
本賞は、日本物理学会が刊行する学術誌Journal of the Physical Society of Japan（JPSJ）における閲読審査に多大なる貢献をしたものに贈られる賞で、2024年度は６名が選出されました。
JPSJ Outstanding Referee賞
Official journal - Jul. 2021
電子と正孔の対凝縮によって生じる特異な絶縁体(励起子絶縁体)が実現しているとして注目を集めているTa2NiSe5において、10万気圧級の高圧力印加により、系は絶縁体から半金属へと変化し、さらに励起子相が消失する臨界圧力近傍で超伝導が出現することを発見した。本論文はJPSJの注目論文に選出され、その研究成果は科学新聞およびオンライン雑誌 Science Japanで紹介された。
Journal of the Physical Society of Japan, Editors' Choice (注目論文)
Official journal - Mar. 2018
Novel Phase Transition and the Pressure Effect in YbFe2Al10-type CeT2Al10 (T = Fe, Ru, Os)
The 23rd Outstanding Paper Award of the Physical Society of Japan, Takashi Nishioka;Yukihiro Kawamura;Tomoaki Takesaka;Riki Kobayashi;Harukazu Kato;Masahiro Matsumura;Kazuto Kodama;Kazuyuki Matsubayashi;Yoshiya Uwatoko
Official journal - Mar. 2016
圧力誘起相転移における臨界現象の研究
第13回 ISSP学術奨励賞 - Mar. 2016
Study of pressure-induced quantum phase transition in strongly correlated electron materials
Young Scientist Award of the Physical Society of Japan (Division 8) - Jan. 2013
新学術領域研究「重い電子系の形成と秩序化」重い電子系研究奨励賞
Paper
- A concise 40 T pulse magnet for condensed matter experiments
Akihiko Ikeda; Kosuke Noda; Kotomi Shimbori; Kenta Seki; Dilip Bhoi; Azumi Ishita; Jin Nakamura; Kazuyuki Matsubayashi; Kazuto Akiba
Journal of Applied Physics, 07 Nov. 2024, Peer-reviwed,
Scientific journal, English - First-order transition under a magnetic ordered state in SmPtSi2
Tomohito NAKANO; Eisuke Takahashi; Shuto Yamaguchi; Naoya Takeda; Klára Uhlířová; Jan Prokleška; Jiří Pospíšil; Vladimír Sechovský; Kazuyuki Matusbayashi; Hanming Ma; Yoshiya Uwatoko
Physica Scripta, 01 Aug. 2024, Peer-reviwed,
Scientific journal - Magnetic ground state of YbCo2Zn20 probed by muon spin relaxation
Wataru Higemoto; Kazuhiko Satoh; Takashi U Ito; Kazuki Ohishi; Yuta Saiga; Masashi Kosaka; Kazuyuki Matsubayashi; Yoshiya Uwatoko
Journal of Physics: Conference Series, IOP Publishing, 2462, 1, 012039-012039, 01 Mar. 2023, Peer-reviwed, Abstract
The cubic compound YbCo2Zn20 has huge electronic specific heat coefficient γ=7900 mJ/molK2 and its ground state could be located in the vicinity of the quantum critical point. To investigate magnetic ground state, we have carried out muon spin relaxation measurements and confirmed non-magnetic ground state with fluctuating tiny magnetic moment.
Scientific journal - Pressure tuning of localization and superconductivity in LaOPbBiS3 and La2O2Bi3AgS6
Y. Yuan; H. Arima; M. Masaoka; Y. Naito; Y. Hijikata; R. Jha; Y. Mizuguchi; K. Matsubayashi
Corresponding, Phys. Rev. B, 105, 064509, Feb. 2022, Peer-reviwed
Scientific journal, English - Interplay between Quadrupolar and Magnetic Interactions in 5d1 Double Perovskite Ba2MgReO6 under Pressure
Hiroto Arima; Yoshiaki Oshita; Daigorou Hirai; Zenji Hiroi; Kazuyuki Matsubayashi
Corresponding, Journal of the Physical Society of Japan, 91, 013702, Dec. 2021, Peer-reviwed
Scientific journal, English - Universal Dynamics of Magnetic Monopoles in Two-Dimensional Kagomé Ice
Hiroshi Takatsu; Kazuki Goto; Taku J. Sato; Jeffrey W. Lynn; Kazuyuki Matsubayashi; Yoshiya Uwatoko; Ryuji Higashinaka; Kazuyuki Matsuhira; Zenji Hiroi; Hiroaki Kadowaki
Journal of the Physical Society of Japan, 90, 123705, Oct. 2021, Peer-reviwed
Scientific journal, English - Hybridization-Gap Formation and Superconductivity in the Pressure-Induced Semimetallic Phase of the Excitonic Insulator Ta2NiSe5
Kazuyuki Matsubayashi; Hidekazu Okamura; Takashi Mizokawa; Naoyuki Katayama; Akitoshi Nakano; Hiroshi Sawa; Tatsuya Kaneko; Tatsuya Toriyama; Takehisa Konishi; Yukinori Ohta; Hiroto Arima; Rina Yamanaka; Akihiko Hisada; Taku Okada; Yuka Ikemoto; Taro Moriwaki; Koji Munakata; Akiko Nakao; Minoru Nohara; Yangfan Lu; Hidenori Takagi; Yoshiya Uwatoko
Lead, Journal of the Physical Society of Japan, The Physical Society of Japan, 90, 6, 074706-074706, Jun. 2021, Peer-reviwed
Scientific journal, English - Magnetic Measurements of Narrow-Gap Semiconductor FeSb2 under High Pressure
Takuya Deguchi; Kazuyuki Matsubayashi; Yoshiya Uwatoko; Takehide Koyama; Takao Kohara; Hiroyuki Nakamura; Yoshifuru Mitsui; Keiichi Koyama
MATERIALS TRANSACTIONS, Japan Institute of Metals, 61, 8, 1476-1479, 01 Jul. 2020
Scientific journal - Superconducting-Gap Anisotropy of Iron Pnictides Investigated via Combinatorial Microwave Measurements
Tatsunori Okada; Yoshinori Imai; Kentaro Kitagawa; Kazuyuki Matsubayashi; Masamichi Nakajima; Akira Iyo; Yoshiya Uwatoko; Hiroshi Eisaki; Atsutaka Maeda
Scientific Reports, NATURE PUBLISHING GROUP, 10, 1, 7046-7064, Apr. 2020, Peer-reviwed, True, One of the most significant issues for superconductivity is clarifying the momentum-dependent superconducting gap Delta (k), which is closely related to the pairing mechanism. To elucidate the gap structure, it is essential to investigate Delta (k) in as many different physical quantities as possible and to crosscheck the results obtained in different methods with each other. In this paper, we report a combinatorial investigation of the superfluid density and the flux-flow resistivity of iron-pnictide superconductors; LiFeAs and BaFe2(As1-xPx)(2) (x=0.3, 0.45). We evaluated Delta (k) by fitting these two-independent quantities with a two-band model simultaneously. The obtained Delta (k) are consistent with the results observed in angle-resolved photoemission spectroscopy (ARPES) and scanning-tunneling spectroscopy (STS) studies. We believe our approach is a powerful method for investigating Delta (k) because it does not require a sample with clean surface unlike ARPES and STS experiments, or a rotational magnetic-field system for direct measurements of the angular dependence of thermodynamic quantities.
Scientific journal, English - Resistive anisotropy of candidate excitonic insulator Ta2NiSe5 under pressure
H. Arima; Y. Naito; K. Kudo; N. Katayama; H. Sawa; M. Nohara; Y.F. Lu; K. Kitagawa; H. Takagi; Y. Uwatoko; K. Matsubayashi
J. Phys.: Conf. Ser. 1609 012001 (2020)., 1609, 1, 012001, 2020, Peer-reviwed, We have measured anisotropic electrical resistivity of quasi-one-dimensional Ta2NiSe5 single crystals under pressure. While the in-plane anisotropy is almost pressure independent, the inter-plane one greatly decreases at P c ∼ 3 GPa accompanied by a pressure-induced semiconductor-semimetal transition. Nevertheless, a similar anomaly in the temperature dependence of in-plane anisotropy has been observed in each phase. This anomaly in the low-pressure phase below P c is regarded as an excitonic transition, and thus both of these anomalies are suppressed with increasing pressure. These results suggest that the suppression of the excitonic binding energy with pressure is caused by the increase of free carrier densities and the inter-plane conductivity.
International conference proceedings, English - Pressure-induced incommensurate antiferromagnetic order in a ferromagnetic B-site ordered double-perovskite Lu2NiMnO6
N. Terada; C.V. Colin; N. Qureshi; T.C. Hansen; K. Matsubayashi; Y. Uwatoko; A.A. Belik
Phys. Rev. B, AMER PHYSICAL SOC, 102, 9, 094412-094412, 2020, Peer-reviwed, We have investigated the pressure effect on magnetic ordering of the ferromagnetic double perovskite Lu2NiMnO6 by magnetization, ac magnetic susceptibility, and neutron diffraction experiments up to 8.0 GPa in order to understand the ferromagnetic-to-antiferromagnetic phase transition by substitution of the A sites in A(2)NiMnO(6) from rare-earth to indium or scandium ions. Strong ferromagnetic spin correlation seen in the susceptibility at low pressure is significantly suppressed by increasing pressure. In a neutron diffraction experiment, the magnetic Bragg reflections associated with ferromagnetic ordering disappear above 4.5 GPa. For the high-pressure region above 4.5 GPa, an antiferromagnetic ordering with long-period incommensurate modulation appears, which is coexistent with ferromagnetic short-range order. From mean-field calculations, we infer that pressure modification of the delicate balance of the competing next-nearest-neighbor exchange interactions between Ni and Ni, or Mn and Mn, plays an important role in the phase transition from ferromagnetic to antiferromagnetic ordering in A(2)NiMnO(6).
Scientific journal, English - High-Pressure Hall Effect Measurement on Ta2NiSe5 as a Candidate for Excitonic Insulator
H. Arima; Y. Naito; K. Kudo; N. Katayama; H. Sawa; M. Nohara; Y. Lu; K. Kitagawa; H. Takagi; Y. Uwatoko; K. Matsubayashi
JPS Conf. Proc., 30, 011031, 2020, Peer-reviwed
International conference proceedings, English - Robust two-gap strong coupling superconductivity associated with low-lying phonon modes in pressurized Nb5Ir3O superconductors
B. Wang; Y. Zhang; S. Xu; K. Ishigaki; K. Matsubayashi; J.-G Cheng; H. Hosono; Y. Uwatoko
Chin. Phys. B, IOP Publishing, 28, 10, 107401-107401, Sep. 2019, Peer-reviwed, We report robust superconducting state and gap symmetry of Nb5Ir3O via electrical transport and specific heat measurements. The analysis of specific heat manifests that Nb5Ir3O is a strongly coupled superconductor with ${\rm{\Delta } }C/{\gamma }_{ { \rm{n } } },{T}_{ { \rm{c } } }\sim 1.91$ and double s-wave superconducting gaps of $2{ { \rm{\Delta } } }_{ { \rm{L } } }(0)/{k}_{ { \rm{B } } },{T}_{ { \rm{c } } }\sim 6.56$ and $2{ { \rm{\Delta } } }_{ { \rm{S } } }(0)/{k}_{ { \rm{B } } },{T}_{ { \rm{c } } }\sim 2.36$ accounting for 90% and 10%, respectively. The $({C}_{ { \rm{p } } }-{\gamma }_{ { \rm{n } } }T)/{T}^{3}$ vs. T plot shows a broad peak at ∼23 K, indicating phonon softening and the appearance of low-lying phonon mode associated with the interstitial oxygen. This behavior explains the monotonic increase of Tc in ${\mathrm{Nb } }_{5},{\mathrm{Ir } }_{3},{ { \rm{O } } }_{(1-\delta )}$ by strengthening the electron–phonon coupling and enlarging the density of states at Fermi level. The Hall coefficient is temperature independent below 200 K, and changes its sign from positive to negative above 250 K, suggesting that carrier is across the hole- to electron-dominant regions and the multi-band electronic structures. On warming, the resistivity shows a gradual crossover from ${T}^{2}$- to ${T}^{3}$-dependence at a critical temperature ${T}^{* }$, and a broad peak at a temperature Tp. The reduced Tc under pressure is linearly correlated with lattice parameters c/a ratio and Tp, suggesting the important phonon contributions in Nb5Ir3O as a phonon-medicated superconductor. Possible physical mechanisms are proposed.
Scientific journal, English - Exotic superconductivity in noncentrosymmetric and magnetic CeNiC2 revealed under high pressure
S. Katano; M. Ito; K. Shibata; J. Gouchi; Y. Uwatoko; K. Matsubayashi; H. Soeda; H. Takahashi
Phys. Rev. B, AMER PHYSICAL SOC, 99, 10, 100501(R)-100501, Mar. 2019, Peer-reviwed, We have found that magnetically ordered noncentrosymmetric CeNiC2 exhibits superconductivity under very high pressures of near 11 GPa. The transition temperature T-c is 3.5 K, the highest in all Ce heavy-fermion superconductors, implying quite strong electron pairings with a high-energy scale. Several physical quantities show diverging features of a quantum phase transition, however, its criticality appears in a rather narrow range of pressure. The upper critical field mu H-0(c2) (T = 0) is estimated to be 18 T, much higher than the Pauli paramagnetic limiting field of 6.5 T, indicating spin-triplet electron pairings correlated with its noncentrosymmetric structure.
Scientific journal, English - Pressure-induced enhancement of superconductivity and quantum criticality in the 12442-type hybrid-structure superconductor KCa2Fe4As4F2
B. Wang; Z.-C. Wang; K. Ishigaki; K. Matsubayashi; T. Eto; J. Sun; J.-G. Cheng; G.-H. Cao; Y. Uwatoko
Phys. Rev. B, American Physical Society, 99, 1, 014501-014501, Feb. 2019, Peer-reviwed
Scientific journal, English - Transport and Thermodynamic Properties of CeRu2Al10 Controlled by Pressure at around Critical Pressure
Y. Kawamura; C. Sekine; K. Matsubayashi; Y. Uwatoko; T. Nishioka
Materials Science Forum, TRANS TECH PUBLICATIONS LTD, 941, 1378-1383, Dec. 2018, Peer-reviwed, We present transport and thermodynamic properties of CeRu2Al10 controlled by pressure in a vicinity of a critical pressure P-C similar to 4GPa, where antiferromagnetic ordering disappears. The resistivity under pressure was measured with DC four terminal method and the AC specific heat under pressure was measured by Joule heating type technique. The pressure was applied by cubic-anvil-apparatus and palm-cubic-anvil-apparatus. The results of AC specific heat indicate TN holds at high temperature up to 3.9 GPa but suddenly disappears above this pressure. We confirmed TN from thermodynamic properties. Although CeRu2Al10 is in a Kondo semiconducting ground state at 4 GPa, temperature dependences of electrical resistivity at 4.6 GPa and 5.9 GPa indicate metallic ground state in these pressures. CeRu2Al10 does not show superconductivity down to 0.7 K at 4.6 GPa and 5.9 GPa.
International conference proceedings, English - Two distinct superconducting phases and pressure-induced crossover from type-II to type-I superconductivity in the spin-orbit-coupled superconductors BaBi3 and SrBi3
B. Wang; X. Luo; K. Ishigaki; K. Matsubayashi; J.-G. Cheng; Y. Sun; Y. Uwatoko
Phys. Rev. B, AMER PHYSICAL SOC, 98, 22, 220506(R)-220506, Dec. 2018, Peer-reviwed, We report two distinct superconducting states with different crystal structures and a crossover from a type-II to a type-I superconductor (SC) in (Ba, Sr)Bi-3. The superconducting parameters are revealed to classify two SCs: BaBi3 is in the weak-coupling limit on the basis of Delta C/gamma T-n(c )similar to 0.67 and 2 Delta/k(B)T(c) similar to 3.28 while SrBi3 is a strong-coupling SC with Delta C/gamma T-n(c )similar to 2.41 and 2 Delta/k(B)T(C) similar to 6.09. A large Kadowaki-Woods ratio (R-KW similar to 3.53a(0)) suggests an enhanced electron-electron scattering in BaBi3. With increasing the pressure, the T-c of BaBi3 decreases linearly at first, and then shows an abrupt increase up to 6.2 K at 0.88 GPa. This behavior can be attributed to a pressured-induced structural transition and the resulting variations of spin-orbit coupling and Fermi structures. T-c of SrBi3 is suppressed monotonously by pressure. The Ginzburg-Landau parameter kappa(GL) of BaBi3 decreases from 10.35 at ambient pressure (AP) to 0.86 at 1.75 GPa, and then tends to saturation. kappa(GL) of SrBi3 decreases from 0.76 at AP to 1/root 2 at 1.20 GPa, which manifests pressured-induced crossover from a type-II to a type-I SC. Possible physical mechanisms are proposed.
Scientific journal, English - Evolution of Magnetic Double Helix and Quantum Critical near a Dome of Superconductivity in CrAs
Matsuda, M; Lin; F. K; Yu, R; Cheng, J-G; Wu, W; Sun, J. P; Zhang, J. H; Sun, P. J; Matsubayashi, K; Miyake, T; Kato, T; Yan, J-Q; Stone, M; B; Si; Qimiao, Luo; J. L; Uwatoko, Y
PHYSICAL REVIEW X, American Physical Society, 8, 3, 297-299, Jul. 2018, Peer-reviwed, At ambient pressure, CrAs undergoes a first-order transition into a double-helical magnetic state at TN=265 K, which is accompanied by a structural transition. The recent discovery of pressure-induced superconductivity in CrAs makes it important to clarify the nature of quantum phase transitions out of the coupled structural/helimagnetic order in this system. Here, we show, via neutron diffraction on the single-crystal CrAs under hydrostatic pressure (P), that the combined order is suppressed at Pc≈10 kbar, near which bulk superconductivity develops with a maximal transition temperature Tc≈2 K. We further show that the coupled order is also completely suppressed by phosphorus doping in CrAs1-xPx at a critical xc≈0.05, above which inelastic neutron scattering evidenced persistent antiferromagnetic correlations, providing a possible link between magnetism and superconductivity. In line with the presence of antiferromagnetic fluctuations near Pc(xc), the A coefficient of the quadratic temperature dependence of resistivity exhibits a dramatic enhancement as P (x) approaches Pc(xc), around which ρ(T) has a non-Fermi-liquid form. Accordingly, the electronic specific-heat coefficient of CrAs1-xPx peaks around xc. These properties provide clear evidence for quantum criticality, which we interpret as originating from a nearly second-order helimagnetic quantum phase transition that is concomitant with a first-order structural transition. Our findings in CrAs highlight the distinct characteristics of quantum criticality in bad metals, thereby bringing out new insights into the physics of unconventional superconductivity such as those occurring in the high-Tc iron pnictides.
Scientific journal, English - Universal phase diagram of superconductivity and charge density wave versus high hydrostatic pressure in pure and Se-doped 1T-TaS2
Wang, Bosen; Liu, Yu; Luo, Xuan; Ishigaki; Kento; Matsubayashi; Kazuyuki, Lu; Wenjian, Sun; Yuping; Cheng, Jinguang; Uwatoko, Yoshiya
PHYSICAL REVIEW B, American Physical Society (APS), 97, 22, 297-299, Jun. 2018, Peer-reviwed
Scientific journal, English - Pressure-Induced Novel Quantum Phase Transition in 4f-Electron Systems
Matsubayashi Kazuyuki; Uwatoko Yoshiya
Butsuri, The Physical Society of Japan, 73, 5, 292-296, 05 May 2018, Peer-reviwed, Understanding the quantum critical behavior in the vicinity of a quantum phase transition remains one of the major challenges of condensed matter physics. In particular, the unconventional criticality, which cannot be explained by the spin fluctuation theory, has attracted much attention in strongly correlated electron systems. In this article, we review our recent findings of a novel quantum phase transition and superconductivity associated with the valence or orbital instability in 4f-electron systems revealed by high pressure experiments.
Scientific journal, Japanese - Fundamental properties of a new samarium compound SmPtSi2
Shuto Yamaguchi; Eisuke Takahashi; Naoki Kase; Tomohito Nakano; Naoya Takeda; Kazuyuki Matsubayashi; Yoshiya Uwatoko
Physica B: Condensed Matter, Elsevier B.V., 536, 297-299, 01 May 2018, Peer-reviwed, We have discovered a new orthorhombic ternary compound SmPtSi2. We succeeded in growing a single crystal of SmPtSi2
prepared a polycrystalline sample of this compound, and measured their susceptibility, specific heat, and resistivity. The temperature dependence of susceptibility of the polycrystalline sample is close to that of Sm3+ at high temperatures, and its specific heat shows anomalies at TH = 8.6 K and TL = 5.6 K. The resistivity of a single crystal of SmPtSi2 shows a hump-type anomaly just below TH and a sudden decrease at TL, indicating that these anomalies are intrinsic and that SmPtSi2 exhibits a two-step transition.
Scientific journal, English - Pressure-induced coherent sliding-layer transition in the excitonic insulator Ta2NiSe5
Akitoshi Nakano; Kento Sugawara; Shinya Tamura; Naoyuki Katayama; Kazuyuki Matsubayashi; Taku Okada; Yoshiya Uwatoko; Kouji Munakata; Akiko Nakao; Hajime Sagayama; Reiji Kumai; Kunihisa Sugimoto; Naoyuki Maejima; Akihiko Machida; Tetsu Watanuki; Hiroshi Sawa
IUCrJ, International Union of Crystallography, 5, Pt 2, 158-165, 01 Mar. 2018, Peer-reviwed, True, The crystal structure of the excitonic insulator Ta2NiSe5 has been investigated under a range of pressures, as determined by the complementary analysis of both single-crystal and powder synchrotron X-ray diffraction measurements. The monoclinic ambient-pressure excitonic insulator phase II transforms upon warming or under a modest pressure to give the semiconducting C-centred orthorhombic phase I. At higher pressures (i.e. >
3GPa), transformation to the primitive orthorhombic semimetal phase III occurs. This transformation from phase I to phase III is a pressure-induced first-order phase transition, which takes place through coherent sliding between weakly coupled layers. This structural phase transition is significantly influenced by Coulombic interactions in the geometric arrangement between interlayer Se ions. Furthermore, upon cooling, phase III transforms into the monoclinic phase IV, which is analogous to the excitonic insulator phase II. Finally, the excitonic interactions appear to be retained despite the observed layer sliding transition.
Scientific journal, English - Emergence of a new valence-ordered structure and collapse of the magnetic order under high pressure in EuPtP
Akihiro Mitsuda; Shigeki Manabe; Masafumi Umeda; Hirofumi Wada; Kazuyuki Matsubayashi; Yoshiya Uwatoko; Masaichiro Mizumaki; Naomi Kawamura; Kiyofumi Nitta; Naohisa Hirao; Yasuo Ohishi; Naoki Ishimatsu
Journal of Physics Condensed Matter, Institute of Physics Publishing, 30, 10, 105603-105603, 19 Feb. 2018, Peer-reviwed, True, The layered hexagonal EuPtP is a rare substance that exhibits two successive valence transitions occurring simultaneously with valence ordering transitions and an antiferromagnetic order. Anticipating that the application of pressure to this sample would induce a new valence-ordered structure and/or a new phenomenon associated with valence fluctuation, we examined the electrical resistivity ρ, the Eu L3-edge x-ray absorption spectroscopy, and the powder x-ray diffraction under high pressure. We found a new valence transition at around P = 2.5 GPa. After the transition, a new valence-ordered structure is realized at the lowest temperature. The valence-ordered structure is inferred to be stacking of (2+: Eu2+ layer, 3+: Eu3+ layer) along the c-axis. Upon further increases in pressure, the valence-ordered structure is suppressed and another valance-ordered phase is realized up to P = 6 GPa. The antiferromagnetic order collapses in the pressure range between 6 GPa and 8 GPa.
Scientific journal, English - Universal phase diagram of superconductivity and charge density wave versus high hydrostatic pressure in pure and Se-doped 1 T- Ta S 2
Wang, Bosen; Liu, Yu; Luo, Xuan; Ishigaki, Kento; Matsubayashi, Kazuyuki; Lu, Wenjian; Sun, Yuping; Cheng, Jinguang; Uwatoko, Yoshiya
Physical Review B, American Physical Society, 97, 22, 220504-220504, 2018
Scientific journal - Anomalous behavior of the ac magnetic susceptibility of the Ce dilute system of CeCu6-yAuy
Shiino T.; Kabeya N.; Imura K.; Deguchi K.; Sato N. K.; Kimura N.; Ochiai A.; Matsubayashi K.
Meeting Abstracts of the Physical Society of Japan, The Physical Society of Japan, 73.2, 1861-1861, 2018
Japanese - Effects of pressure and magnetic field on superconductivity in ZrTe3: local pair-induced superconductivity
S. Tsuchiya; K. Matsubayashi; K. Yamaya; S. Takayanagi; S. Tanda; Y. Uwatoko
NEW JOURNAL OF PHYSICS, IOP PUBLISHING LTD, 19, 063004, Jun. 2017, Peer-reviwed, In this work, the origin of the highly anisotropic superconducting transition in ZrTe3, where the resistance along the a axis, Ra, is reduced at 4 K but those along the b axis, R-b, and c ' axis, R-c ', are reduced at 2 K, was explored with the application of a magnetic field and pressure by the electrical resistance measurements. We found that the behavior of the upper critical field and its anisotropy as well as the pressure dependence determined by the Ra measurements are quite similar to those of Rb. Moreover, the excess conductivity for Rb indicates anomalous behavior. These results support an unconventional origin for the anisotropic transition rather than conventional superconducting fluctuation. The reduction in Ra is due to filamentary superconductivity. (SC) induced by locally bound electron pairs (local pairs), which correspond to bi-polarons, and the transition of Rb corresponds to the emergence of bulk SC originating from the Cooper pairs triggered by the transfer of the local pairs.
Scientific journal, English - Pressure-induced bulk superconductivity in a layered transition-metal dichalcogenide 1T-tantalum selenium
Bosen Wang; Yu Liu; Kento Ishigaki; Kazuyuki Matsubayashi; Jinguang Cheng; Wenjian Lu; Yuping Sun; Yoshiya Uwatoko
PHYSICAL REVIEW B, AMER PHYSICAL SOC, 95, 22, Jun. 2017, Peer-reviwed, We report pressure-driven superconductivity (SC) in the vicinity of a commensurate charge-density wave (CCDW) in transition-metal dichalcogenides (TMDs) 1T-TaSe2 by simultaneous resistivity and ac susceptibility. The superconducting phase enters at 4.5 GPa and bulk SC emerges along with the collapse of the CCDW phase at a critical pressure P-c similar to 6.5 GPa. Higher than P-c, the superconducting transition temperature (T-c) keeps increasing linearly, without a dome-shaped superconducting diagram in our pressure range. T-c reaches similar to 5.3 K at 15 GPa, which is the highest among all 1T-TMDs. A comprehensive analysis shows that electronic correlations of the CCDW phase open energy gaps, which prohibit Cooper pairing, while the superconducting channels and CCDW domain wall coexist in three dimensions above P-c. The evolutions of the Fermi surface and the softening of phonon modes under pressure are proposed to explain the monotonic increase of T-c. The findings reveal the interplay of CCDW and SC in 1T-TaSe2 by a clean method, viz., high pressure, and shed light on the underlying superconducting mechanism in the relevant systems.
Scientific journal, English - Zn-site Substitution Effect in YbCo2Zn20
Riki Kobayashi; Haruki Takamura; Yasuyuki Higa; Yoichi Ikeda; Kazuyuki Matsubayashi; Yoshiya Uwatoko; Hideki Yoshizawa; Naofumi Aso
Journal of Physics: Conference Series, Institute of Physics Publishing, 807, 1, 012009, 06 Apr. 2017, Peer-reviwed, We have investigated the substitution effect of YbCo2(Zn1-xTx)20 (T = Cu, Ga, and Cd) systems by using the experiments of X-ray powder diffraction (XRPD), specific heat, magnetic susceptibility, magnetization, and electrical resistivity in order to find out a material that approaches a quantum critical point by chemical pressure. The XRPD and electrical resistivity measurements clarify that the Cu-substitution makes the lattice constants shrink and keeps the magnetic electrical resistivity high, while the Ga- and the Cd-substitution show opposite relation of the Cu-substitution. However, we could not detect clear substitution effect in the specific heat, magnetic susceptibility, and magnetization measurements of Cu-substitution system within our experiments. It is necessary that to study the Cu-substitution samples that have higher x value at lower temperature.
International conference proceedings, English - Unique Pressure versus Temperature Phase Diagram for Antiferromagnets WEu2Ni3Ge5 and EuRhSi3
Miho Nakashima; Yasushi Amako; Kazuyuki Matsubayashi; Yoshiya Uwatoko; Masato Nada; Kiyohiro Sugiyama; Masayuki Hagiwara; Yoshinori Haga; Tetsuya Takeuchi; Ai Nakamura; Hiromu Akamine; Keisuke Tomori; Tomoyuki Yara; Yosuke Ashitomi; Masato Hedo; Takao Nakama; Yoshichika Onuki
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, PHYSICAL SOC JAPAN, 86, 3, 034708, Mar. 2017, Peer-reviwed, We studied the magnetic properties of the antiferromagnets Eu2Ni3Ge5 and EuRhSi3 by measuring their electrical resistivity, specific heat, magnetic susceptibility, magnetization, and thermoelectric power, together with the electrical resistivities at high pressures of up to 15 GPa. These compounds have almost divalent Eu ions at ambient pressure and order antiferromagnetically with a successive change in the antiferromagnetic structure at T-N = 19K and T'(N) = 17K in Eu2Ni3Ge5, and at T-N = 49K and T'(N) = 45K in EuRhSi3. Magnetic field versus temperature (H - T) phase diagrams were constructed for both compounds from the magnetization measurements. The Neel temperature in Eu2Ni3Ge5 was found to increase up to 7 GPa but to decrease continuously with further increasing pressure, without the so-called valence transition. Under a high pressure of 15 GPa, Kondo-like behavior of the electrical resistivity was observed, suggesting the existence of the heavy-fermion state at low temperatures. A similar trend is likely to occur in EuRhSi3. The present P-T phase diagrams for both compounds are the first cases that are reminiscent of the phase diagram of EuCu2( SixGe1-x)(2).
Scientific journal, English - Unique Pressure versus Temperature Phase Diagram for Antiferromagnets WEu2Ni3Ge5 and EuRhSi3
Miho Nakashima; Yasushi Amako; Kazuyuki Matsubayashi; Yoshiya Uwatoko; Masato Nada; Kiyohiro Sugiyama; Masayuki Hagiwara; Yoshinori Haga; Tetsuya Takeuchi; Ai Nakamura; Hiromu Akamine; Keisuke Tomori; Tomoyuki Yara; Yosuke Ashitomi; Masato Hedo; Takao Nakama; Yoshichika Onuki
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, PHYSICAL SOC JAPAN, 86, 3, Mar. 2017, Peer-reviwed, We studied the magnetic properties of the antiferromagnets Eu2Ni3Ge5 and EuRhSi3 by measuring their electrical resistivity, specific heat, magnetic susceptibility, magnetization, and thermoelectric power, together with the electrical resistivities at high pressures of up to 15 GPa. These compounds have almost divalent Eu ions at ambient pressure and order antiferromagnetically with a successive change in the antiferromagnetic structure at T-N = 19K and T'(N) = 17K in Eu2Ni3Ge5, and at T-N = 49K and T'(N) = 45K in EuRhSi3. Magnetic field versus temperature (H - T) phase diagrams were constructed for both compounds from the magnetization measurements. The Neel temperature in Eu2Ni3Ge5 was found to increase up to 7 GPa but to decrease continuously with further increasing pressure, without the so-called valence transition. Under a high pressure of 15 GPa, Kondo-like behavior of the electrical resistivity was observed, suggesting the existence of the heavy-fermion state at low temperatures. A similar trend is likely to occur in EuRhSi3. The present P-T phase diagrams for both compounds are the first cases that are reminiscent of the phase diagram of EuCu2( SixGe1-x)(2).
Scientific journal, English - Two-carrier analyses of the transport properties of black phosphorus under pressure
Kazuto Akiba; Atsushi Miyake; Yuichi Akahama; Kazuyuki Matsubayashi; Yoshiya Uwatoko; Masashi Tokunaga
PHYSICAL REVIEW B, AMER PHYSICAL SOC, 95, 11, Mar. 2017, Peer-reviwed, We report on the electronic transport properties of black phosphorus and analyze them using a two-carrier model in a wide range of pressure up to 2.5 GPa. In a semiconducting state at 0.29 GPa, the remarkable nonlinear behavior in the Hall resistance is reasonably reproduced by assuming the coexistence of two kinds of holes with different densities and mobilities. On the other hand, two-carrier analyses of the magnetotransport properties above 1.01 GPa suggest the coexistence of high-mobility electron and hole carriers that have almost the same densities, i.e., nearly compensated semimetallic nature of black phosphorus. In the semimetallic state, analyses of both the two-carrier model and quantum oscillations indicate a systematic increase in the carrier densities as pressure increases. An observed sign inversion of Hall resistivity at low magnetic fields suggests the existence of high-mobility electrons (10(5)cm(2)V(-1)s(-1)), which is roughly ten times larger than that of holes, in the semimetallic black phosphorus. We conclude that the extremely large positive magnetoresistance that has been observed in the semimetallic state cannot be reproduced by a conventional two-carrier model.
Scientific journal, English - Pressure-Induced Metallization in Iron-Based Ladder Compounds Ba1-xCsxFe2Se3
Takafumi Hawai; Chizuru Kawashima; Kenya Ohgushi; Kazuyuki Matsubayashi; Yusuke Nambu; Yoshiya Uwatoko; Taku J. Sato; Hiroki Takahashi
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, PHYSICAL SOC JAPAN, 86, 2, Feb. 2017, Peer-reviwed, Electrical resistivity measurements have been performed on the iron-based ladder compounds Ba1-xCsxFe2Se3 (x = 0, 0.25, 0.65, and 1) under high pressure. A cubic anvil press was used up to 8.0 GPa, whereas further higher pressure was applied using a diamond anvil cell up to 30.0 GPa. Metallic behavior of the electrical conductivity was confirmed in the x = 0.25 and 0.65 samples for pressures greater than 11.3 and 14.4 GPa, respectively, with the low-temperature log T upturn being consistent with weak localization of 2D electrons due to random potential. At pressures higher than 23.8 GPa, three-dimensional Fermi-liquid-like behavior was observed in the latter sample. No metallic conductivity was observed in the parent compounds BaFe2Se3 (x = 0) up to 30.0 GPa and CsFe2Se3 (x = 1) up to 17.0 GPa. The present results indicate that the origins of the insulating ground states in the parent and intermediate compounds are intrinsically different; the former is a Mott insulator, whereas the latter is an Anderson insulator owing to the random substitution of Cs for Ba.
Scientific journal, English - Superconducting, Fermi surface, and magnetic properties in SrTGe3 and EuTGe3 (T: transition metal) with the Rashba-type tetragonal structure
Masashi Kakihana; Hiromu Akamine; Keisuke Tomori; Kengo Nishimura; Atsushi Teruya; Ai Nakamura; Fuminori Honda; Dai Aoki; Miho Nakashima; Yasushi Amako; Kazuyuki Matsubayashi; Yoshiya Uwatoko; Tetsuya Takeuchi; Takanori Kida; Masayuki Hagiwara; Yoshinori Haga; Etsuji Yamamoto; Hisatomo Harima; Masato Hedo; Takao Nakama; Yoshichika Onuki
JOURNAL OF ALLOYS AND COMPOUNDS, ELSEVIER SCIENCE SA, 694, 439-451, Feb. 2017, Peer-reviwed, We succeeded in growing single crystals of SrTGe3 (T: transition metal) by the In-flux method and measured the electrical resistivity, specific heat, and de Haas-van Alphen (dHvA) effect. We confirmed superconductivity in SrPdGe3 and SrPtGe3, which was previously observed using polycrystal samples, and also found superconductivity for SrRhGe3, SrIrGe3, and SrNiGe3. Furthermore, from the results of dHvA experiments and energy band calculations, Fermi surfaces of SrlrGe(3) are found to split into two similar Fermi surfaces, reflecting the Rashba-type non-centrosymmetric tetragonal structure. We also grew single crystals of EuTGe3 by the same In-flux method and studied magnetic properties, especially focusing on magnetism of EuIrGe3 with a Neel temperature T-N=12.2 K and a successive magnetic transition T-N=7.3 K. The magnetic phase diagram of EuIrGe3 is found to consist of three antiferromagnetic phases named AF1, AF2, and AF3. A critical field He reaching a saturated moment of 7 mu(B)/Eu is determined as H-c similar or equal to 160 kOe from a high-field magnetization curve. We proposed a simple helical magnetic structure based on the Dzyaloshinskii-Moriya interaction. (C) 2016 Elsevier B.V. All rights reserved.
Scientific journal, English - A Glimpse of Novel States in a Non-Kramers Doublet System
Matsubayashi, Kazuyuki
JPSJ News and Comments, The Physical Society of Japan, 14, 04-04, 2017
Scientific journal - Divalent, trivalent, and heavy fermion states in Eu compounds
Y. Onuki; A. Nakamura; F. Honda; D. Aoki; T. Tekeuchi; M. Nakashima; Y. Amako; H. Harima; K. Matsubayashi; Y. Uwatoko; S. Kayama; T. Kagayama; K. Shimizu; S. Esakki Muthu; D. Braithwaite; B. Salce; H. Shiba; T. Yara; Y. Ashitomi; H. Akamine; K. Tomori; M. Hedo; T. Nakama
PHILOSOPHICAL MAGAZINE, TAYLOR & FRANCIS LTD, 97, 36, 3399-3414, 2017, Peer-reviwed, Most of the Eu compounds are in the divalent (Eu2+) electronic state and order magnetically. On the other hand, the Eu-trivalent (Eu3+) compounds exist but are small in number. An energy difference between the Eu2+ and Eu3+ states is, however, not extremely large. Therefore, the valence transition occurs in some Eu compounds. We present the characteristic properties of the Eu compounds from several viewpoints: a canting magnetisation in the Eu2+-antiferromagnets, the Fermi surface property in the Eu3+ compounds of EuPd3 and EuCo2Si2, the heavy fermion state in EuNi2P2, the temperature-induced valence transition in EuPd2Si2, the pressure-induced valence transition in EuRh2Si2 and EuRu2P2, and the heavy fermion state approaching to the quantum critical point with increasing pressure in Eu2Ni3Ge5.
Scientific journal, English - Iron arsenides with three-dimensional FeAs layer networks: Can(n+1)/2(Fe1-xPtx)((2+3n))Ptn(n-1)/2 As(n+1)(n+2)/2 (n=2, 3)
Naoyuki Katayama; Seiichiro Onari; Kazuyuki Matsubayashi; Yoshiya Uwatoko; Hiroshi Sawa
SCIENTIFIC REPORTS, NATURE PUBLISHING GROUP, 6, 419-428, Dec. 2016, Peer-reviwed, True, We report the comprehensive studies between synchrotron X-ray diffraction, electrical resistivity and magnetic susceptibility experiments for the iron arsenides Can(n+ 1)/2(Fe1-xPtx)((2+ 3n)) Ptn(n-1)/2As(n+ 1)(n+ 2)/2 for n = 2 and 3. Both structures crystallize in the monoclinic space group P2(1)/m (# 11) with threedimensional FeAs structures. The horizontal FeAs layers are bridged by inclined FeAs planes through edge-sharing FeAs5 square pyramids, resulting in triangular tunneling structures rather than the simple layered structures found in conventional iron arsenides. n = 3 system shows a sign of superconductivity with a small volume fraction. Our first-principles calculations of these systems clearly indicate that the Fermi surfaces originate from strong Fe-3d characters and the three-dimensional nature of the electric structures for both systems, thus offering the playgrounds to study the effects of dimensionality on high T-c superconductivity.
Scientific journal, English - Competition of superconductivity with the structural transition in Mo3Sb7
G. Z. Ye; J-G Cheng; J-Q Yan; J. P. Sun; K. Matsubayashi; T. Yamauchi; T. Okada; Q. Zhou; D. S. Parker; B. C. Sales; Y. Uwatoko
PHYSICAL REVIEW B, AMER PHYSICAL SOC, 94, 22, 419-428, Dec. 2016, Peer-reviwed, Prior to the superconducting transition at T-c approximate to 2.3 K, Mo3Sb7 undergoes a symmetry-lowering, cubic-totetragonal structural transition at T-s = 53 K. We have monitored the pressure dependence of these two transitions by measuring the resistivity of Mo3Sb7 single crystals under various hydrostatic pressures up to 15 GPa. The application of external pressure enhances T-c but suppresses T-s until P-c approximate to 10 GPa, above which a pressureinduced first-order structural transition takes place and is manifested by the phase coexistence in the pressure range 8 <= P <= 12 GPa. The cubic phase above 12 GPa is also found to be superconducting with a higher T-c approximate to 6 K that decreases slightly with further increasing pressure. The variations with pressure of T-c and T-s satisfy the Bilbro-McMillan equation, i. e. (TcTs1-n)-T-n = constant, thus suggesting the competition of superconductivity with the structural transition that has been proposed to be accompanied with a spin-gap formation at T-s. Our first-principles calculations suggest the importance of magnetism that competes with the superconductivity in Mo3Sb7.
Scientific journal, English - Long-range magnetic order in the Heisenberg pyrochlore antiferromagnets Gd2Ge2O7 and Gd2Pt2O7 synthesized under high pressure
X. Li; Y. Q. Cai; Q. Cui; C. J. Lin; Z. L. Dun; K. Matsubayashi; Y. Uwatoko; Y. Sato; T. Kawae; S. J. Lv; C. Q. Jin; J. -S. Zhou; J. B. Goodenough; H. D. Zhou; J. -G. Cheng
PHYSICAL REVIEW B, AMER PHYSICAL SOC, 94, 21, 439-451, Dec. 2016, Peer-reviwed, Gd2Sn2O7 and Gd2Ti2O7 have been regarded as good experimental realizations of the classical Heisenberg pyrochlore antiferromagnet with dipolar interaction. The former was found to adopt the Palmer-Chalker state via a single, first-order transition at T-N approximate to 1K, while the latter enters a distinct, partially ordered state through two successive transitions at T-N1 approximate to 1K and T-N2 = 0.75 K. To shed more light on their distinct magnetic ground states, we have synthesized two more gadolinium-based pyrochlore oxides, Gd2Ge2O7 andGd(2)Pt(2)O(7), under highpressure conditions and performed detailed characterizations via x-ray powder diffraction, dc and ac magnetic susceptibility, and specific heat measurements down to 100 mK. We found that both compounds enter a long-range antiferromagnetically ordered state through a single, first-order transition at TN = 1.4K for Gd2Ge2O7 and TN = 1.56K for Gd2Pt2O7, with the specific heat anomaly similar to that of Gd2Sn2O7 rather than Gd2Ti2O7. Interestingly, the low-temperature magnetic specific heat values of both Gd2Ge2O7 and Gd2Pt2O7 were found to follow nicely the T-3 dependence as expected for a three-dimensional antiferromagnet with gapless spin-wave excitations. We have rationalized the enhancement of TN in terms of the reduced Gd-Gd distances for the chemically pressurized Gd2Ge2O7 and the addition of extra superexchange pathways through the empty Pt -eg orbitals for Gd2Pt2O7. Our current study has expanded the family of gadolinium-based pyrochlores and permits us to achieve a better understanding of their distinct magnetic properties in a more comprehensive perspective.
Scientific journal, English - Pressure-induced valence change toward the QCP in 4f-electron compounds determined by X-ray absorption spectroscopy
K. Matsubayashi; N. Kawamura; M. Mizumaki; N. Ishimatsu
HIGH PRESSURE RESEARCH, TAYLOR & FRANCIS LTD, 36, 3, 419-428, Sep. 2016, Peer-reviwed, In strongly correlated electron systems, a fundamental understanding of the quantum critical behavior in the vicinity of a magnetic quantum critical point (QCP) remains one of the important issues for decades. In particular, the unconventional criticality, which cannot be explained by the spin fluctuation theory, has attracted much attention in 4f electron systems, and the role of the valence instability has been discussed both from theoretical and experimental points of view. Here, we present our systematic high pressure study of X-ray absorption spectra on YbNi3Ga9 and EuFe2As2, revealing the characteristic pressureinduced valence crossover and possibly the relevance of the valence instability to the physical properties near the magnetic QCP.
Scientific journal, English - Magnetic properties of Mn
1.9 Cu0.1 Sb under high pressure
Yoshihiro Matsumoto; Kazuyuki Matsubayashi; Yoshiya Uwatoko; Masahiko Hiroi; Yoshifuru Mitsui; Keiichi Koyama
AIP Conference Proceedings, AMER INST PHYSICS, 1763, 26 Aug. 2016, © 2016 Author(s). Magnetization measurements were carried out for polycrystalline Mn1.9Cu0.1Sb in magnetic fields up to 5 T in the 10-300 K temperature range under high pressures up to 1 GPa in order to investigate the magnetic properties and the thermal transformation arrest (TTA) phenomenon under high pressures. The spin-reorientation temperature increased from 202 K for 0.1 MPa to 244 K for 1 GPa, whereas the transition temperature from the ferrimagnetic (FRI) to antiferromagnetic (AFM) state did not drastically change at ∼116 K. The magnetic relaxation behavior from the FRI to AFM state was observed in 10 < T ≤ 70 K, which was analyzed using the Kohlrausch-Williams-Watts model. Obtained results indicated that the TTA phenomenon of Mn1.9Cu0.1Sb was suppressed by the application of high pressures.
International conference proceedings, English - Magnetic and Fermi Surface Properties of Ferromagnets EuPd2 and EuPt2
Ai Nakamura; Hiromu Akamine; Yousuke Ashitomi; Fuminori Honda; Dai Aoki; Tetsuya Takeuchi; Kazuyuki Matsubayashi; Yoshiya Uwatoko; Yasutomi Tatetsu; Takahiro Maehira; Masato Hedo; Takao Nakama; Yoshichika Onuki
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, PHYSICAL SOC JAPAN, 85, 8, 439-451, Aug. 2016, Peer-reviwed, We succeeded in growing single crystals of the ferromagnets EuPd2 and EuPt2 with the Laves-type cubic structure by the Bridgman method, namely, heating constituting materials in a Mo crucible up to a high temperature of about 1500 degrees C. The ferromagnetic properties of EuPd2 and EuPt2 with Curie temperatures of 74 and 100 K, respectively, were confirmed from the results of electrical resistivity, specific heat, and magnetization measurements. The ordered moment is 7 mu(B)/Eu, revealing the Eu-divalent ferromagnetism. The present Eu-divalent electronic state is found to be robust against high pressures of up to 8 GPa and is not changed into the Eu-trivalent state. We also carried out de Haas-van Alphen (dHvA) experiments for EuPd2. The detected dHvA branches in EuPd2 are well explained by the relativistic linearized augmented plane wave (RLAPW) energy band calculations for SrPd2, revealing a closed hole Fermi surface and compensated four closed electron Fermi surfaces.
Scientific journal, English - Absence of superconductivity in the collapsed tetragonal phase of KFe2As2 under hydrostatic pressure
Bosen Wang; Kazuyuki Matsubayashi; Jinguang Cheng; Taichi Terashima; Kunihiro Kihou; Shigeyuki Ishida; Chul-Ho Lee; Akira Iyo; Hiroshi Eisaki; Yoshiya Uwatoko
PHYSICAL REVIEW B, AMER PHYSICAL SOC, 94, 2, Jul. 2016, Peer-reviwed, Temperature dependence of resistivity on KFe2As2 single crystals down to 20 mK was measured under various hydrostatic pressures up to 17.5 GPa generated in a cubic-anvil cell. With increasing the pressure, the superconducting transition of tetragonal KFe2As2 was suppressed gradually and disappears completely at similar to 11 GPa, which was related to the weakening of electronic correlations and/or critical fluctuations under pressure. In sharp contrast to previous reports, no superconducting phase emerges upon further increasing pressures until the collapsed tetragonal KFe2As2 forms. We argue that such a discrepancy can be attributed to the different pressure apparatus or homogeneity.
Scientific journal, English - Dome-shaped magnetic order competing with high-temperature superconductivity at high pressures in FeSe
J. P. Sun; K. Matsuura; G. Z. Ye; Y. Mizukami; M. Shimozawa; K. Matsubayashi; M. Yamashita; T. Watashige; S. Kasahara; Y. Matsuda; J-Q. Yan; B. C. Sales; Y. Uwatoko; J-G. Cheng; T. Shibauchi
NATURE COMMUNICATIONS, NATURE PUBLISHING GROUP, 7, Jul. 2016, Peer-reviwed, The coexistence and competition between superconductivity and electronic orders, such as spin or charge density waves, have been a central issue in high transition-temperature (T-c) superconductors. Unlike other iron-based superconductors, FeSe exhibits nematic ordering without magnetism whose relationship with its superconductivity remains unclear. Moreover, a pressure-induced fourfold increase of Tc has been reported, which poses a profound mystery. Here we report high-pressure magnetotransport measurements in FeSe up to similar to 15 GPa, which uncover the dome shape of magnetic phase superseding the nematic order. Above similar to 6GPa the sudden enhancement of superconductivity (T-c <= 38.3 K) accompanies a suppression of magnetic order, demonstrating their competing nature with very similar energy scales. Above the magnetic dome, we find anomalous transport properties suggesting a possible pseudogap formation, whereas linear-in-temperature resistivity is observed in the normal states of the high-T-c phase above 6 GPa. The obtained phase diagram highlights unique features of FeSe among iron-based superconductors, but bears some resemblance to that of high-T-c cuprates.
Scientific journal, English - T/B scaling without quasiparticle mass divergence: YbCo2Ge4
Akito Sakai; Kentaro Kitagawa; Kazuyuki Matsubayashi; Makoto Iwatani; Philipp Gegenwart
PHYSICAL REVIEW B, AMER PHYSICAL SOC, 94, 4, Jul. 2016, Peer-reviwed, YbCo2Ge4 is a clean paramagnetic Kondo lattice which displays non-Fermi-liquid behavior. We report a detailed investigation of the specific heat, magnetic Gruneisen parameter (Gamma(mag)), and temperature derivative of the magnetization (M) on a high-quality single crystal at temperatures down to 0.1 K and magnetic fields up to 7 T.Gamma(mag) and dM/dT display a divergence upon cooling and obey T/B scaling. Similar behavior has previously been found in several other Yb-based Kondo lattices and related to a zero-field quantum critical point without fine tuning of pressure or composition. However, in the approach of B -> 0 the electronic heat capacity coefficient of YbCo2Ge4 saturates at low T, excluding ferromagnetic quantum criticality. This indicates that T/B scaling is insufficient to prove a zero-field quantum critical point.
Scientific journal, English - Magnetic and structural properties of metamagnetic MnCo0.92Fe0.08Ge Compound
K. Ozono; Y. Mitsui; M. Hiroi; R. Umetsu; K. Takahashi; K. Matsubayashi; Y. Uwatoko; K. Koyama
Materials Transactions, 57, 3, 316-320, Mar. 2016, Peer-reviwed, The magnetic and structural properties of ferromagnetic MnCo0.92Fe0.08Ge were investigated by magnetization and X-ray powder diffraction measurements in magnetic fields up to 5 T. The compound showed first-order transition between the paramagnetic and ferromagnetic state with a thermal hysteresis of approximately 24 K, which was accompanied by the martensitic transformation from the hexagonal Ni2In-type structure to the orthorhombic TiNiSi-type structure in the vicinity of 275 K. The cell volume expanded by 4.1% during the martensitic transformation. The magnetic moment of MnCo0.92Fe0.08Ge was estimated to be 111Am2 kg-1 (3.7μB/f.u.) at 10 K. The compound showed both metamagnetic transition and magnetic field-induced martensitic transformation.
Scientific journal, English - Kondo Effect in CeXc (X-c = S, Se, Te) Studied by Electrical Resistivity Measurements under High Pressure
Yuya Hayashi; Shun Takai; Takeshi Matsumura; Hiroshi Tanida; Masafumi Sera; Kazuyuki Matsubayashi; Yoshiya Uwatoko; Akira Ochiai
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, PHYSICAL SOC JAPAN, 85, 3, Mar. 2016, Peer-reviwed, We have measured the electrical resistivity of cerium monochalcogenides, CeS, CeSe, and CeTe, under high pressures of up to 8 GPa. The pressure dependences of the antiferromagnetic ordering temperature T-N, crystal field splitting, and the ln T anomaly of the Kondo effect have been studied to cover the entire region from the magnetic ordering regime at low pressure to the Fermi liquid regime at high pressure. T-N initially increases with increasing pressure, and starts to decrease at high pressure as expected from Doniach's diagram. Simultaneously, the ln T behavior in the resistivity is enhanced, indicating the enhancement of the Kondo effect by pressure. It is also characteristic of CeXc that the crystal field splitting rapidly decreases at a common rate of -12.2K/GPa. This leads to the increase in the degeneracy of the f state and the further enhancement of the Kondo effect. It is shown that the pressure-dependent degeneracy of the f state is a key factor for understanding the pressure dependence of T-N, the Kondo effect, magnetoresistance, and the peak structure in the temperature dependence of resistivity.
Scientific journal, English - Superconducting and Fermi Surface Properties of Single Crystal Zr2Co
Atsushi Teruya; Masashi Kakihana; Tetsuya Takeuchi; Dai Aoki; Fuminori Honda; Ai Nakamura; Yoshinori Haga; Kazuyuki Matsubayashi; Yoshiya Uwatoko; Hisatomo Harima; Masato Hedo; Takao Nakama; Yoshichika Onuki
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, PHYSICAL SOC JAPAN, 85, 3, Mar. 2016, Peer-reviwed, We succeeded in growing single crystals of a superconductor Zr2Co with the tetragonal structure by the Bridgman method and carried out electrical resistivity, magnetic susceptibility, magnetization, specific heat, and de Haas van Alphen (dHvA) experiments. Superconductivity is a characteristic revealing that the electronic specific heat at 1.45K in the form of C-e/T in the superconducting state increases not linearly but as a function of root H up to a magnetic field close to the upper critical field H-c2 = 11 kOe. The superconducting transition temperature T-sc is found to increase markedly with increasing pressure from T-sc = 5.2K at ambient pressure to 9.5K at 8 GPa. From the dHvA experiment, several kinds of dHvA branches are detected, which are well explained by the results of the energy band calculation. The main conduction electrons are Zr-4d and Co-3d electrons.
Scientific journal, English - Pressure dependence of the magnetic ground states in MnP
M. Matsuda; F. Ye; S. E. Dissanayake; J. -G. Cheng; S. Chi; J. Ma; H. D. Zhou; J. -Q. Yan; S. Kasamatsu; O. Sugino; T. Kato; K. Matsubayashi; T. Okada; Y. Uwatoko
PHYSICAL REVIEW B, AMER PHYSICAL SOC, 93, 10, Mar. 2016, Peer-reviwed, MnP, a superconductor under pressure, exhibits a ferromagnetic order below T-C similar to 290 K followed by a helical order with the spins lying in the ab plane and the helical rotation propagating along the c axis below T-s similar to 50 K at ambient pressure. We performed single-crystal neutron diffraction experiments to determine the magnetic ground states under pressure. Both T-C and T-s are gradually suppressed with increasing pressure and the helical order disappears at similar to 1.2 GPa. At intermediate pressures of 1.8 and 2.0 GPa, the ferromagnetic order first develops and changes to a conical or two-phase (ferromagnetic and helical) structure with the propagation along the b axis below a characteristic temperature. At 3.8 GPa, a helical magnetic order appears below 208 K, which hosts the spins in the ac plane and the propagation along the b axis. The period of this b axis modulation is shorter than that at 1.8 GPa. Our results indicate that the magnetic phase in the vicinity of the superconducting phase may have a helical magnetic correlation along the b axis.
Scientific journal, English - 21pBL-11 Study of c-f mixing in CeX_c(X_c=S,Se,Te) by electric resistivity under pressure and magnetic field II
Hayashi Y.; Matsumura T.; Sera M.; Umeo K.; Matsubayashi K.; Uwatoko Y.; Ochiai A.
Meeting Abstracts of the Physical Society of Japan, The Physical Society of Japan (JPS), 71, 2292-2292, 2016
Japanese - Long-range magnetic order in the Heisenberg pyrochlore antiferromagnets G d 2 G e 2 O 7 and G d 2 P t 2 O 7 synthesized under high pressure
Li, X.; Cai, YQ; Cui, Q.; Lin, CJ; Dun, ZL; Matsubayashi, K.; Uwatoko, Y.; Sato, Y.; Kawae; Tatsuya; Lv; SJ and o
Physical Review B, American Physical Society, 94, 21, 214429-214429, 2016
Scientific journal - Competition of superconductivity with the structural transition in M o 3 S b 7
Ye, GZ; Cheng, J-G.; Yan, J-Q.; Sun, JP; Matsubayashi, K.; Yamauchi, T.; Okada, T.; Zhou, Q.; Parker; David S.; Sales, Brian C.
Physical Review B, American Physical Society, 94, 22, 224508-224508, 2016
Scientific journal - Pressure-Induced Superconductivity in Strongly Correlated Systems under High Quality Pressure Condition
MATSUBAYASHI Kazuyuki; UWATOKO Yoshiya
The Review of High Pressure Science and Technology, The Japan Society of High Pressure Science and Technology, 26, 1, 8-13, 2016, In this article, recent advances in cubic anvil cell (CAC) using an integrated-fin gasket technique, which extends the pressure range up to 16 GPa, were reviewed. We demonstrate that the high quality 10 GPa-class pressure using CAC allows us to extract the intrinsic properties, and to explore novel phenomena in strongly correlated electron systems.
Japanese - 20pBC-10 SrCu_2(BO_3)_2のテラヘルツ領域における圧力下ESR測定II
平尾 祐樹; 櫻井 敬博; 太田 仁; 大久保 晋; 肘井 敬吾; 松林 和幸; 上床 美也; 工藤 一貴; 小池 洋二
日本物理学会講演概要集, 一般社団法人日本物理学会, 71, 1206-1206, 2016
Japanese - 20pPSB-25 Development of the apparatus to measure the field-angle-resolved specific heat under pressure for the study of superconducting gap structure
Kittaka S.; Matsubayashi K.; Uwatoko Y.; Sakakibara T.
Meeting Abstracts of the Physical Society of Japan, The Physical Society of Japan (JPS), 71, 2128-2128, 2016
Japanese - 21aAL-11 Magnetic and Fermi Surface Properties of EuTGe_3 (T: transition metal) and SrTGe_3
Kakihana M.; Akamine H.; Nishimura K.; Teruya A.; Nakashima M.; Amako Y.; Takeuchi T.; Matsubayashi K.; Uwatoko Y.; Harima H.; Uchima K.; Hedo M.; Nakama T.; Onuki Y.
Meeting Abstracts of the Physical Society of Japan, The Physical Society of Japan (JPS), 71, 2164-2164, 2016
Japanese - 21aAL-12 Change of Valence and Heavy Fermion State in Eu_2Ni_3Ge_5 and EuRhSi_3
Onuki Y; Akamine H.; Ashitomi Y.; Nakamura A.; Nakashima M.; Amako Y.; Takeuchi T.; Matsubayashi K.; Uwatoko Y.; Hedo M.; Nakama T.; Shiba H.
Meeting Abstracts of the Physical Society of Japan, The Physical Society of Japan (JPS), 71, 2165-2165, 2016
Japanese - 20pPSB-39 Physical properties in a heavy fermion compound Yb(Co_<1-x>Ni_x)_2Zn_<20> III
Higa Y.; Kobayashi R.; Aso N.; Ikeda Y.; Yoshizawa H.; Matsubayashi K.; Uwatoko Y.
Meeting Abstracts of the Physical Society of Japan, The Physical Society of Japan (JPS), 71, 2142-2142, 2016
Japanese - Substitution effect of Zn site in a heavy fermion compound YbCo2Zn20 II
Aso Naofumi; Kudeken Takahiro; Tsuken Ryo; Tamaki Goshi; Kohama Norihito; Takamura Haruki; Higa Yasuyuki; Kobayashi Riki; Matsubayashi Kazuyuki; Uwatoko Yoshiya
Meeting Abstracts of the Physical Society of Japan, The Physical Society of Japan, 71, 2129-2129, 2016,YbCo_2_Zn_20_は、巨大な電子比熱係数 γ = 8 J/mol・K^2^ を有する重い電子系化合物として知られている。約1.5GPa以上の圧力で反強磁性相が観測され、YbCo_2_Zn_20_は量子臨界点に近い電子状態にあると考えられる。本研究ではYbCo_2_Zn_20_のZn元素位置にCu, Cd, Ga, Ag, Au, Mg元素を置換し単結晶育成を行った。今学会では、Zn置換の効果と量子臨界点近傍の振る舞いについての研究結果について報告する。
Japanese - 22aPS-8 Non-Fermi liquid behavior in PrV_2Al_<20> under pressure and magnetic field
Matsubayashi K.; Tsujimoto M.; Nakatsuji S.; Kitagawa K.; Uwatoko Y.
Meeting Abstracts of the Physical Society of Japan, The Physical Society of Japan (JPS), 71, 2402-2402, 2016
Japanese - Effect of pressure on the CDW transitions of 1T-TaX2 (x=S and Se)
Wang Bosen; Liu Yu; Ishigaki Kento; Matsubayashi Kazuyuki; Cheng Jinguang; Lu Wenjian; Sun Yuping; Uwatoko Yoshiya
Meeting Abstracts of the Physical Society of Japan, The Physical Society of Japan, 71, 2038-2038, 2016,2-3個のCDW転移温度を持つ、1T-TaS2および1T-TaSe2において、電気抵抗の圧力効果の測定を行った。いずれの試料も、常圧下の半導体的振る舞いから、高圧下での金属的振る舞いを観測することが出来た。さらに低温に下げると、1T-TaSでは、これまでの報告通り、超伝導を確認することが出来た。1T-TaSe2においても興味深い結果を得ることが出来たので、両者の圧力効果を比較しつつ、報告する。
Japanese - Magnetic field-temperature phase diagrams under pressure and Non-Fermi liquid behavior in antiferroquadrupolar PrV2Al20
Matsubayashi K.; Tsujimoto M.; Nakatsuji S.; Kitagawa K.; Uwatoko Y.
Meeting Abstracts of the Physical Society of Japan, The Physical Society of Japan, 71, 1812-1812, 2016,PrV_2_Al_20_は圧力および磁場印加によって反強四極子秩序が抑制されると非フェルミ液体的な挙動を示す。興味深いことに、この非フェルミ液体的振る舞いが観測される広範囲な圧力・磁場においてスケーリング則が成り立ち、その温度依存性は四極子近藤格子モデルから期待されるものとよく一致する。講演では、上記の実験と解析結果の詳細について紹介し、非フェミル液体的振る舞いと超伝導発現との関連について議論する。
Japanese - Transport and Magnetic Properties of EuAl4 and EuGa4
Ai Nakamura; Taro Uejo; Fuminori Honda; Tetsuya Takeuchi; Hisatomo Harima; Etsuji Yamamoto; Yoshinori Haga; Kazuyuki Matsubayashi; Yoshiya Uwatoko; Masato Hedo; Takao Nakama; Yoshichika Onuki
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, PHYSICAL SOC JAPAN, 84, 12, 83-87, Dec. 2015, Peer-reviwed, We succeeded in growing a single crystal of the Eu-divalent compound EuAl4 with the BaAl4-type tetragonal structure by the Al self-flux method and measured the electrical resistivity, magnetic susceptibility, magnetization, specific heat, and thermoelectric power. EuAl4 orders antiferromagnetically below T-N1 = 15.4 K, with three successive antiferromagnetic transitions at T-N2 = 13.2 K, T-N3 = 12.2 K, and T-N4 = 10.0 K. The latter two transitions are of the first-order. The corresponding magnetization curve indicates three successive metamagnetic transitions with hystereses and saturates above 16 kOe. We observed a plausible characteristic feature of the charge density wave (CDW) below T-CDW = 140 K. We also studied an effect of pressure on the electronic state by measuring the electrical resistivity and thermoelectric power. T-CDW is found to decrease with increasing pressure at a rate of dT(CDW)/dP = -54.7K/GPa and becomes zero at about 2.5 GPa. The present antiferromagnetic ordering is, however, found to be stable at higher pressures up to 7 GPa in EuAl4. On the other hand, the different characteristic CDW was observed in EuGa4, not at ambient pressure but above 1 GPa, and T-CDW increases with increasing pressure. Above 6 GPa, we found that the antiferromagnetic ordering is changed into another first-order-like phase transition. Its characteristic feature is similar to that of the valence transition, and the heavy fermion state is realized at low temperatures.
Scientific journal, English - Electrical Transport in the Quasi-Two-Dimensional Ionic Mott Insulator M2P-TCNQF(4) under High Pressures
Takehara Ryosuke; Miyagawa Kazuya; Miyamoto Tatsuya; Okamoto Hiroshi; Taniguchi Hiromi; Matsubayashi Kazuyuki; Uwatoko Yoshiya; Kanoda Kazushi
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, PHYSICAL SOC JAPAN, 84, 10, 15 Oct. 2015, Peer-reviwed, We performed electrical resistivity measurements for the quasi-two-dimensional ionic Mott insulator M2P-TCNQF(4) (M2P: 5,10-dihydro-5,10-dimethylphenazine, TCNQF(4): 2,3,5-tetrafluoro-7,7,8,8-tetracyanoquinodimethane) under high pressures up to 80 kbar, to search for a metallic state emerging from an ionic insulator. At room temperature, the resistivity is markedly decreased by five orders of magnitude with increasing pressure up to 80 kbar. Although the temperature dependence of resistivity shows insulating behavior at 80 kbar, the activation energy of 0.36 eV at ambient pressure is reduced to 0.077 eV at 80 kbar, indicating that the system is brought close to the metallic state. At 60 and 80 kbar, low-temperature resistivity is described by variable range hopping rather than by thermal activation over a gap, which suggests that some disorder is induced in the system at high pressures.
Scientific journal, English - Pressure-induced superconductivity in the iron-based ladder material BaFe2S3
Hiroki Takahashi; Akira Sugimoto; Yusuke Nambu; Touru Yamauchi; Yasuyuki Hirata; Takateru Kawakami; Maxim Avdeev; Kazuyuki Matsubayashi; Fei Du; Chizuru Kawashima; Hideto Soeda; Satoshi Nakano; Yoshiya Uwatoko; Yutaka Ueda; Taku J. Sato; Kenya Ohgushi
NATURE MATERIALS, NATURE PUBLISHING GROUP, 14, 10, 1008-+, Oct. 2015, Peer-reviwed, True, All the iron-based superconductors identified so far share a square lattice composed of Fe atoms as a common feature, despite having different crystal structures. In copper-based materials, the superconducting phase emerges not only in square-lattice structures but also in ladder structures. Yet iron-based superconductors without a square-lattice motif have not been found, despite being actively sought out. Here, we report the discovery of pressure-induced superconductivity in the iron-based spin-ladder material BaFe2S3, a Mott insulator with striped-type magnetic ordering below similar to 120 K. On the application of pressure this compound exhibits a metal-insulator transition at about 11 GPa, followed by the appearance of superconductivity below T-c = 14 K, right after the onset of the metallic phase. Our findings indicate that iron-based ladder compounds represent promising material platforms, in particular for studying the fundamentals of iron-based superconductivity.
Scientific journal, English - High Pressure Effect on the Superconductivity in VN
Bosen Wang; Kazuyuki Matsubayashi; Yoshiya Uwatoko; Kenya Ohgushi
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, PHYSICAL SOC JAPAN, 84, 10, 1007-1012, Oct. 2015, Peer-reviwed, We revisited the superconductivity in a vanadium-based superconductor VNx with a special focus on its high-pressure effect. We found that the electronic specific heat at low temperature follows a single gap BCS-type function, indicating the s-wave symmetry of superconducting gap. We also revealed that the superconducting transition temperature (T-c) enhances as the pressure increases up to 8 GPa, giving a positive differential pressure coefficient of 0.09K=GPa. The enhancement of T-c was discussed in terms of the suppressed spin fluctuations, and the phonon softening.
Scientific journal, English - Frequency Extension to the THz Range in the High Pressure ESR System and Its Application to the Shastry-Sutherland Model Compound SrCu2(BO3)(2)
Hitoshi Ohta; Takahiro Sakurai; Ryosuke Matsui; Kohei Kawasaki; Yuki Hirao; Susumu Okubo; Kazuyuki Matsubayashi; Yoshiya Uwatoko; Kazutaka Kudo; Yoji Koike
JOURNAL OF PHYSICAL CHEMISTRY B, AMER CHEMICAL SOC, 119, 43, 13755-13761, Oct. 2015, Peer-reviwed, True, We have made a survey of ceramics for the inner parts of the transmission-type pressure cell to achieve the high pressure and the high transmission in the THz range. By using the optimal combination of ZrO2-based ceramic and Al2O3 ceramic, we have succeeded in obtaining a pressure up to 1.5 GPa and a frequency region up to 700 GHz simultaneously. We show the high-pressure ESR results of the Shastry-Sutherland compound SrCu2(BO3)(2) as an application. We observed the direct ESR transition modes between the singlet ground state and the triplet excited states up to a pressure of 1.51 GPa successfully, and obtained the precise pressure dependence of the gap energy. The gap energy is directly proved to be suppressed by the pressure. Moreover, we found that the system approaches the quantum critical point with pressure by comparing the obtained data with the theory. This result also shows the usefulness of high-pressure ESR measurement in the THz region to study quantum spin systems.
Scientific journal, English - Development of High-Pressure ESR System Using Micro-coil
Kohei Kawasaki; Takahiro Sakurai; Eiji Ohmichi; Susumu Okubo; Hitoshi Ohta; Kazuyuki Matsubayashi; Yoshiya Uwatoko
APPLIED MAGNETIC RESONANCE, SPRINGER WIEN, 46, 9, 987-992, Sep. 2015, Peer-reviwed, We have developed the high-pressure electron spin resonance (ESR) system using a micro-coil in the frequency region up to around 2 GHz and potentially 10 GHz. The hybrid-type piston-cylinder pressure cell whose maximum pressure reaches 4 GPa was used. In this study, we obtained ESR spectra at 2.3 GPa successfully, which can never be obtained by the single-layer piston-cylinder pressure cell. The minimum detectable spin number was estimated to be the order of 10(12) spins/G. Moreover, it is shown that the sensitivity can be improved by two orders of magnitude using the field modulation technique. This high-pressure ESR technique is a promising one to achieve the sensitivity and the high pressure simultaneously.
Scientific journal, English - Development of High-Pressure and Multi-Frequency ESR System and Its Application to Quantum Spin System
Takahiro Sakurai; Ryosuke Matsui; Kohei Kawasaki; Susumu Okubo; Hitoshi Ohta; Kazuyuki Matsubayashi; Yoshiya Uwatoko; Kazutaka Kudo; Yoji Koike
APPLIED MAGNETIC RESONANCE, SPRINGER WIEN, 46, 9, 1007-1012, Sep. 2015, Peer-reviwed, We have developed a high-pressure and multi-frequency electron spin resonance (ESR) system in the submillimeter wave region. The pressure is generated by the piston-cylinder pressure cell whose inner parts are all made of ceramics. The requirements for the inner parts of the pressure cell are toughness and transmission in the submillimeter wave region and they enable us to observe the transmitted light through a sample subjected to high pressure. It was found that both properties can be achieved by the combination of the inner parts made of the ZrO2-based ceramic and the Al2O3 ceramic. For the Shastry-Sutherland compound SrCu2(BO3)(2), we observed the direct ESR transition from the singlet ground state to the first excited triplet sates at 1.5 GPa successfully in the frequency region from 300 to 700 GHz.
Scientific journal, English - Gap structure seen in magnetic penetration depth and flux-flow resistivity of 122 Fe-based superconductors
Maeda, A.; Okada, T.; Takahashi, H.; Nabeshima, F.; Imai, Y.; Kitagawa, K.; Matsubayashi, K.; Uwatoko, Y.; Nakajima, M.; Iyo; A
Quantum Matter, American Scientific Publishers, 4, 4, 308-313, Aug. 2015, Peer-reviwed
Scientific journal, English - Magnetic Order in the Frustrated Ising Quasi-One Dimensional Compound NaCo(acac)(3)center dot Benzene
Yoshitomo Karaki; Kentaro Kuga; Kenta Kimura; Satoru Nakatsuji; Kazuyuki Matsubayashi; Yoshiya Uwatoko
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, PHYSICAL SOC JAPAN, 84, 8, 13755-13761, Aug. 2015, Peer-reviwed, We report the results of susceptibility, magnetization curve, and specific heat measurements on single crystals of NaCo(acac)(3)center dot benzene, which forms a triangular lattice on the ab-plane with Ising ferromagnetic chains along the c-axis. We found a long-range order below 62 mK by specific heat measurement, a steplike increase in susceptibility at this temperature, and a plateau of one-third of the full moment in the M-H curve at 20 mK. We also observed a spin relaxation that obeys the Arrhenius law in the ordered state. The existence of a partially disordered antiferromagnetic state is discussed on the basis of the results.
Scientific journal, English - Zr-based bulk metallic glass as a cylinder material for high pressure apparatuses
Kazuki Komatsu; Koji Munakata; Kazuyuki Matsubayashi; Yoshiya Uwatoko; Yoshihiko Yokoyama; Kazumasa Sugiyama; Masaaki Matsuda
HIGH PRESSURE RESEARCH, TAYLOR & FRANCIS LTD, 35, 3, 254-262, Jul. 2015, Peer-reviwed, Zirconium-based bulk metallic glass (Zr-based BMG) has outstanding properties as a cylinder material for piston-cylinder high pressure apparatuses and is especially useful for neutron scattering. The piston-cylinder consisting of a Zr-based BMG cylinder with outer/inner diameters of 8.8/2.5mm sustains pressures up to 1.81GPa and ruptured at 2.0GPa, with pressure values determined by the superconducting temperature of lead. The neutron attenuation of Zr-based BMG is similar to that of TiZr null-scattering alloy and more transparent than that of CuBe alloy. No contamination of sharp Bragg reflections is observed in the neutron diffraction pattern for Zr-based BMG. The magnetic susceptibility of Zr-based BMG is similar to that of CuBe alloy; this leads to a potential application for measurements of magnetic properties under pressure.
Scientific journal, English - Anomalous Quantum Transport Properties in Semimetallic Black Phosphorus
Kazuto Akiba; Astushi Miyake; Yuichi Akahama; Kazuyuki Matsubayashi; Yoshiya Uwatoko; Hayato Arai; Yuki Fuseya; Masashi Tokunaga
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, PHYSICAL SOC JAPAN, 84, 7, 83-87, Jul. 2015, Peer-reviwed, Magnetoresistance in single crystals of black phosphorus is studied at ambient and hydrostatic pressures. In the semiconducting states at pressures below 0.71 GPa, the magnetoresistance shows periodic oscillations, which can be ascribed to the magneto-phonon resonance that is characteristic of high-mobility semiconductors. In the semimetallic state above 1.64 GPa, both transverse and longitudinal magnetoresistances show a considerable increase while exhibiting superposed Shubnikov-de Haas oscillations. The observed small Fermi surfaces, high mobilities, and light effective masses of carriers in semimetallic black phosphorus are comparable to those in the representative elemental semimetals of bismuth and graphite.
Scientific journal, English - Pressure-Induced Valence Transition and Heavy Fermion State in Eu2Ni3Ge5 and EuRhSi3
Ai Nakamura; Tomoya Okazaki; Miho Nakashima; Yasushi Amako; Kazuyuki Matsubayashi; Yoshiya Uwatoko; Shuei Kayama; Tomoko Kagayama; Katsuya Shimizu; Taro Uejo; Hiromu Akamine; Masato Hedo; Takao Nakama; Yoshichika Onuki; Hiroyuki Shiba
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, PHYSICAL SOC JAPAN, 84, 5, 83-87, May 2015, Peer-reviwed, We succeeded in growing single crystals of Eu2Ni3Ge5 and EuRhSi3 by the In-flux method, and measured the electrical resistivity under pressures. Both compounds are Eu-divalent antiferromagnets with the Neel temperatures T-N = 18.6 and 47.7 K, respectively. With increasing pressure, the resistivity in Eu2Ni3Ge5 indicates a clear kink at T-v = 220 K under 8.0 GPa, for example, which corresponds to a valence transition. The valence of Eu ions deviates from divalence toward trivalence. Correspondingly, antiferromagnetic ordering disappears completely. The low-temperature resistivity is, surprisingly, very similar to the resistivity of a well-known heavy fermion superconductor CeCu2Si2, possessing a two-peak-structure based on the Kondo effect. In fact, the A value of the resistivity rho = rho(0) + AT(2) in the Fermi liquid relation becomes large, A = 0.3 mu Omega.cm/K-2 at 8.0 GPa. The similar characteristic features are observed in another compound EuRhSi3.
Scientific journal, English - Effect of Pressure on the Electronic state in Eu-Divalent EuTIn4 (T: Ni, Pd, Pt, Au) Compounds
M Hedo; Y Hiranaka; A Nakamura; K Tomori; F Honda; Y Haga; H Harima; K Matsubayashi; Y Uwatoko; T Nakama; Y Onuki
Journal of Physics: Conference Series (JPCS), 592, 1, 012047-1-012047-7, 18 Mar. 2015, Peer-reviwed, We grew single crystals of Eu-divalent antiferromagnets EuTIn4 (T: Ni, Pd, Pt, Au) by the In-self ux method, with the constitution of Eu:T:In = 1.1:1:30. Single crystals are characteristic in shape, being long along the orthorhombic [100] direction. We measured the electrical resistivity, specific heat, magnetic susceptibility, and de Haas-van Alphen effect for these compounds, together with the electrical resistivity under pressure for EuTIn4 (T: Ni, Pd, Pt). Under pressure, the Eu-divalent electronic state is often changed into the Eu-trivalent state, revealing the valence transition. In the present experiments, the valence transition was, however, not observed even at high pressures up to 8 GPa for these compounds, but a sharp resistivity drop was observed just below the Néel temperature under pressure. This is most likely due to a change of the magnetic structure.
International conference proceedings, English - Pressure Induced Superconductivity on the border of Magnetic Order in MnP
J. -G. Cheng; K. Matsubayashi; W. Wu; J. P. Sun; F. K. Lin; J. L. Luo; Y. Uwatoko
PHYSICAL REVIEW LETTERS, AMER PHYSICAL SOC, 114, 11, 83-87, Mar. 2015, Peer-reviwed, We report the discovery of superconductivity on the border of long-range magnetic order in the itinerant-electron helimagnet MnP via the application of high pressure. Superconductivity with T-sc approximate to 1 K emerges and exists merely near the critical pressure P-c approximate to 8 GPa, where the long-range magnetic order just vanishes. The present finding makes MnP the first Mn-based superconductor. The close proximity of superconductivity to a magnetic instability suggests an unconventional pairing mechanism. Moreover, the detailed analysis of the normal-state transport properties evidenced non-Fermi-liquid behavior and the dramatic enhancement of the quasiparticle effective mass near P-c associated with the magnetic quantum fluctuations.
Scientific journal, English - Electron transport in TTF-CA under High pressures
Ryosuke Takehara; Kazuya Miyagawa; Kazushi Kanoda; Tatsuya Miyamoto; Hiroyuki Matsuzaki; Hiroshi Okamoto; Hiromi Taniguchi; Kazuyuki Matsubayashi; Yoshiya Uwatoko
PHYSICA B-CONDENSED MATTER, ELSEVIER SCIENCE BV, 460, 83-87, Mar. 2015, Peer-reviwed, We investigate the electron transport in the neutral-ionic transition material, tetrathialulvalene-p-chloranil (TTF-CA), under extremely high pressures up to 82.5 kbar, using a cubic anvil system. At room temperature, as pressure is applied, the resistivity steeply decreases in the neutral phase and exhibits a minimum followed by an increase, which reproduces the previously reported results. However, resistivity is found to become insensitive to pressure above 20 kbar, where the ionic phase is stabilized. The robust transport characteristics of the ionic phase is in contrast with the pressure-sensitive transport in the neutral phase. The temperature dependence of resistivity is insulating in the whole pressure range up to 82.5 kbar but shows breaks in the activation plot at certain temperatures, suggesting that some phase transition occurs in the ionic phase. (C) 2014 Elsevier B.V. All rights reserved.
Scientific journal, English - Charge disproportionation and the pressure-induced insulator-metal transition in cubic perovskite PbCrO3
Jinguang Cheng; K. E. Kweon; S. A. Larregola; Yang Ding; Y. Shirako; L. G. Marshall; Z. -Y. Li; X. Li; Antonio M. dos Santos; M. R. Suchomel; K. Matsubayashi; Y. Uwatoko; G. S. Hwang; John B. Goodenough; J. -S. Zhou
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, NATL ACAD SCIENCES, 112, 6, 1670-1674, Feb. 2015, Peer-reviwed, The perovskite PbCrO3 is an antiferromagnetic insulator. However, the fundamental interactions leading to the insulating state in this single-valent perovskite are unclear. Moreover, the origin of the unprecedented volume drop observed at a modest pressure of P = 1.6 GPa remains an outstanding problem. We report a variety of in situ pressure measurements including electron transport properties, X-ray absorption spectrum, and crystal structure study by X-ray and neutron diffraction. These studies reveal key information leading to the elucidation of the physics behind the insulating state and the pressure-induced transition. We argue that a charge disproportionation 3Cr(4+) -> 2Cr(3+) + Cr6+ in association with the 6s-p hybridization on the Pb2+ is responsible for the insulating ground state of PbCrO3 at ambient pressure and the charge disproportionation phase is suppressed under pressure to give rise to a metallic phase at high pressure. The model is well supported by density function theory plus the correlation energy U (DFT + U) calculations.
Scientific journal, English - Pressure-Induced Valence Crossover and Novel Metamagnetic Behavior near the Antiferromagnetic Quantum Phase Transition of YbNi3Ga9
K. Matsubayashi; T. Hirayama; T. Yamashita; S. Ohara; N. Kawamura; M. Mizumaki; N. Ishimatsu; S. Watanabe; K. Kitagawa; Y. Uwatoko
PHYSICAL REVIEW LETTERS, AMER PHYSICAL SOC, 114, 8, 83-87, Feb. 2015, Peer-reviwed, We report electrical resistivity, ac magnetic susceptibility, and x-ray absorption spectroscopy measurements of intermediate valence YbNi3Ga9 under pressure and magnetic field. We have revealed a characteristic pressure-induced Yb valence crossover within the temperature-pressure phase diagram, and a first-order metamagnetic transition is found below P-c similar to 9 GPa where the system undergoes a pressure-induced antiferromagnetic transition. As a possible origin of the metamagnetic behavior, a critical valence fluctuation emerging near the critical point of the first-order valence transition is discussed on the basis of the temperature-field-pressure phase diagram.
Scientific journal, English - Correlation between T-c and Crystal Structure in S-Doped FeSe Superconductors under Pressure: Studied by X-ray Diffraction of FeSe0.8S0.2 at Low Temperatures
Takahiro Tomita; Hiroki Takahashi; Hiroyuki Takahashi; Hironari Okada; Yoshikazu Mizuguchi; Yoshihiko Takano; Satoshi Nakano; Kazuyuki Matsubayashi; Yoshiya Uwatoko
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, PHYSICAL SOC JAPAN, 84, 2, 13755-13761, Feb. 2015, Peer-reviwed, Electrical resistivity and magnetization measurements were performed on polycrystalline Fe-based superconductors, FeSe1-xSx (x = 0.1, 0.2, and 0.3), under hydrostatic pressures of up to 8 GPa to investigate the pressure dependence of the superconducting transition temperature, T-c(P). For FeSe1-xSx (0.1 <= x <= 0.3), T-c decreased slightly with increasing pressure up to 1 GPa, but at higher pressures, T-c increased to more than 30 K. The maximum T-c(onset) values were 35.8 K (x = 0.1) and 36.3 K (x = 0.2) under pressures of 5 and 6 GPa, respectively. The change observed in the T-c pressure dependence from a concave curve to a convex curve is unusual. To investigate this T-c(P) behavior, we measured the crystal structure of FeSe0.8S0.2 by X-ray diffraction under various pressures. The results indicate that T-c(P) is strongly correlated with the anion (sulfur/selenium) height, as previously observed in FeSe.
Scientific journal, English - 23pBC-13 Study of c-f mixing in CeX_c(X_c=S,Se,Te) by electric resistivity under high pressure II
Hayashi Y.; Takai S.; Matsumura T.; Sera M.; Matsubayashi K.; Uwatoko Y.; Ochiai A.
Meeting Abstracts of the Physical Society of Japan, The Physical Society of Japan (JPS), 70, 2298-2298, 2015
Japanese - Pressure-induced valence crossover and novel metamagnetic behavior near the antiferromagnetic quantum phase transition of YbNi 3 Ga 9
Matsubayashi, K.; Hirayama, T.; Yamashita, T.; Ohara, Shigeo; Kawamura, N.; Mizumaki, M.; Ishimatsu, N.; Watanabe, S.; Kitagawa, K.; Uwatoko, Y.
Physical review letters, American Physical Society, 114, 8, 086401-086401, 2015
Scientific journal - Point-Contact Spectroscopy of Heavy Fermion Compounds CeCu
6 and CeAl3 in Magnetic Field
G. Motoyama; S. Ogawa; K. Matsubayashi; K. Matsubayashi; K. Fujiwara; K. Miyoshi; S. Nishigori; T. Mutou; A. Yamaguchi; A. Sumiyama; Y. Uwatoko
Physics Procedia, 75, 296-302, 01 Jan. 2015, © 2015 The Authors. Published by Elsevier B.V. We have carried out point-contact spectroscopy measurements on CeCu6and CeAl3to study these heavy fermion states. Temperature and magnetic field dependences of the point-contact spectra were observed in detail. At the lowest temperature of 0.4 K, differential resistance spectra of CeCu6and CeAl3as function of bias voltage exhibit each distinct minimum structure and additional small peak structure. Temperature evolutions of these spectra started at temperatures related to the Kondo effect, although the minimum and the peak structure emerged in reverse between both spectra of two compounds. In magnetic fields, both structures monotonically change with no distinct change without a change of curvature of magnetic field dependence of magnitude of differential resistance at zero bias voltage at critical magnetic field of meta-magnetization. This behavior in magnetic field is different from that of CeAl2, which shows antiferromagnetic ordering. This result may suggest that PCS is able to discriminate between heavy fermion state and antiferromagnetic state.
International conference proceedings - 17aPS-73 Thermoelectric Power and Pressure Effect in Eu_2Ni_3Ge_5 that causes the valence transition
Tomori K.; Yara T.; Nakashima M.; Amako Y.; Uwatoko Y.; Matsubayashi K.; Hedo M.; Nakama T.; Onuki Y.
Meeting Abstracts of the Physical Society of Japan, The Physical Society of Japan (JPS), 70, 1867-1867, 2015
Japanese - Crystal Field Effects in Polymorphic Compound TbIr
2 Si2
Toru Shigeoka; Yuya Kurata; Takuya Nakata; Tetsuya Fujiwara; Kazuyuki Matsubayashi; Yoshiya Uwatoko
Physics Procedia, 75, 837-844, 2015, The tetragonal ternary compound TbIr2Si2 shows polymorphism; the ThCr2Si2-type structure as a low temperature phase (I-phase) and the CaBe2Ge2-type one as a high temperature phase (P-phase) exist. In order to compare with magnetism of the morphs, magnetic measurements were performed on the I- and P-phase single crystals. The magnetic behavior changes drastically depending on the structure. The TbIr2Si2 (I) shows an antiferromagnetic ordering below TN=80 K, a strong uniaxial magnetic anisotropy with the easy [001] direction, and isotropic magnetic behavior in the basal plane. The [001] magnetization shows a clear two-step metamagnetic transition: an Ising-like behavior at low temperatures. On the other hand, the TbIr2Si2 (P) has the comparatively low ordering temperature of TN1=11.5 K and an additional transition temperature of TN2=5 K, and exhibits an easy-plane magnetic anisotropy with the easy [100] direction. A strong magnetic anisotropy appears for high magnetic fields between the directions in the basal plane. Multi-step metamagnetic processes appear. In the both phases, the χ-T behavior suggests the existence of component-separated magnetic transitions. The ab-component of magnetic moments orders at the higher transition temperature TN1 for the P-phase compound, which is contrast to the I-phase behavior; the c-component orders firstly at TN in the I-phase. The crystalline electric field analysis was made, and the CEF effects explain the different of magnetic anisotropy between the both phases.
International conference proceedings - The Successive component-separated magnetic transitions on pseudoternary compounds Ho1-xGdxRh2Si2
Toru Shigeoka; Tetsuhiro Morita; Tetsuya Fujiwara; Kazuyuki Matsubayashi; Yoshiya Uwatoko
20TH INTERNATIONAL CONFERENCE ON MAGNETISM, ICM 2015, ELSEVIER SCIENCE BV, 75, 845-852, 2015, Magnetic measurements on pseudoternary compounds Ho1-xGdxRh2Si2, which substitute Gd having no quadrupole for Ho, were performed. They exhibit a successive component-separated magnetic transition; the c-and ab-components of magnetic moments independently order at different temperatures T-N1 and T-N2, respectively. The partial ordered state, a frustration appears for T-N1 > T > T-N2: for the phase II in the magnetic phase diagrams. In the ordered phase, step-like metamagnetic processes appear for T-N2 > T; two-step ones appear along the [001] and [100] directions, and a one-step one appears along the [110] direction. The B-T magnetic phase diagrams were constructed. There are six, four and three ordered phases in the B-001-T, B-100-T and B-110-T phase diagram, respectively. Two diagrams of the basal plane directions, B-100-T and B-110-T, resemble each other. Some interesting or peculiar phase boundaries appear. The Gd composition x dependence of transition temperatures is determined. The transition temperatures T-N1 and T-N2 increase with increasing x. The x-dependency of T-N1 is well scaled by the de Gennes factor: (g-1)(2)J(J+1) whereas the transition of T-N2 is not scaled. Some magnetic features declare that quadrupole interactions play an important role in this compound system.
International conference proceedings, English - Pressure Effect on Transport Properties of EuNi(Si1-xGex)(3) Compounds
Kiyoharu Uchima; Yoshinao Takaesu; Nozomi Arakaki; Sentaro Hirakawa; Masashi Kakihana; Yosuke Ashitomi; Kengo Nishimura; Fuminori Suzuki; Tomoyuki Yara; Masato Hedo; Takao Nakama; Katsuma Yagasaki; Kazuyuki Matsubayashi; Yoshiya Uwatoko
20TH INTERNATIONAL CONFERENCE ON MAGNETISM, ICM 2015, ELSEVIER SCIENCE BV, 75, 884-889, 2015, The compounds of EuNi(Si1-xGex)(3) order antiferromagnetically. At the temperature T-C below the Neel temperature T-N, EuNiSi3 (x = 0) shows an additional magnetic transition into ferromagnetic state. T-N decreases monotonously with increasing the Ge composition x. The Curie temperature T-C decreases rapidly with increasing x and vanishes at the critical composition x approximate to 0.3. We have measured the electrical resistivity and thermopower of EuNi(Si0.8Ge0.2)(3), which is a compound near to the boundary between the ferromagnetic and antiferromagnetic ground states in the phase diagram for EuNi(Si1-xGex) 3 system, under pressures up to 1.8 GPa at temperatures from 2 to 300 K. The anomalies in rho(T) and S(T) curves of EuNi(Si0.8Ge0.2)(3) are observed at T-C = 16 K and T-N = 34 K at ambient pressure. Both T-C and T-N increase linearly with increasing pressure. The temperature variations of. and S of EuNi(Si0.8Ge0.2)(3) at P = 1.8 GPa are almost the same as those of EuNi(Si0.9Ge0.1)(3) (x=0.1) at ambient pressure, revealing that the effect of pressure on T-N and T-C is the same as that of the increase of Si concentration. The pressure and atomic composition dependences of the magnetic transition temperatures T-N and T-C can be expressed by using the Gruneisen parameters. These results indicate that the changes of T-N and T-C are attributed to the change of atomic volume induced by the applying pressure or the atomic substitution.
International conference proceedings, English - 16aPS-14 Magnetization measurements in RMn_2Ge_2 under high pressure
Fujiwara T.; Matsubayashi K.; Uwatoko Y.; Shigeoka T.
Meeting Abstracts of the Physical Society of Japan, The Physical Society of Japan (JPS), 70, 720-720, 2015
Japanese - 22pBA-10 Heavy fermion-like behavior in EuRu_2P_2 under high pressure
Fujiwara T.; Matsubayashi K.; Uwatoko Y.; Shigeoka T.
Meeting Abstracts of the Physical Society of Japan, The Physical Society of Japan (JPS), 70, 2227-2227, 2015
Japanese - 21pAH-4 Magnetic properties of polymorphic compounds RIr_2Si_2 single crystal II
Shigeoka T.; Nakata T.; Fujiwara T.; Matsubayashi K.; Uwatoko Y.
Meeting Abstracts of the Physical Society of Japan, The Physical Society of Japan (JPS), 70, 1067-1067, 2015
Japanese - Point-Contact Spectroscopy of Heavy Fermion Compounds CeCu6 and CeAl3 in Magnetic Field
Motoyama G; Ogawa S; Matsubayashi K; Fujiwara K; Miyoshi K; Nishigori S; Mutou T; Yamaguchi A; Sumiyama A; Uwatoko Y
20TH INTERNATIONAL CONFERENCE ON MAGNETISM, ICM 2015, 75, 296-302, 2015, Peer-reviwed - 17aDC-3 The Fermi Surface of Semimetallic Black Phosphorus from the Magnetoresistance Measurements under High Pressure
Akiba K.; Miyake A.; Sato Y.; Akahama Y.; Matsubayashi K.; Uwatoko Y.; Tokunaga M.
Meeting Abstracts of the Physical Society of Japan, The Physical Society of Japan (JPS), 70, 1791-1791, 2015
Japanese - 17aDC-4 Observation of Fermi Surface of Semi-metallic Black Phosphorus by Magnetization Measurements under High Pressure
Sato Y.; Akiba K.; Miyake A.; Akahama Y.; Matsubayashi K.; Uwatoko Y.; Tokunaga M.
Meeting Abstracts of the Physical Society of Japan, The Physical Society of Japan (JPS), 70, 1792-1792, 2015
Japanese - 16aPS-119 Sensitivity improvement and application of high pressure, high field and multifrequency ESR system III
Sakurai T.; Hirao Y.; Okubo S.; Ohta H.; Matsubayashi K.; Uwatoko Y.
Meeting Abstracts of the Physical Society of Japan, The Physical Society of Japan (JPS), 70, 793-793, 2015
Japanese - 17pCM-4 High pressure ESR measurement of SrCu2(BO3)2 in THz region
Hirao Y.; Sakurai T.; Ohta H.; Okubo S.; Hara S.; Matsuoka E.; Sugawara H.; Matsubayashi K.; Uwatoko Y.; Kudo K.; Koike Y.
Meeting Abstracts of the Physical Society of Japan, The Physical Society of Japan (JPS), 70, 896-896, 2015
Japanese - 21pPSA-61 Sensitivity improvement and application of high pressure, high field and multifrequency ESR system II
Sakurai T.; Matsui R.; Kawasaki K.; Okubo S.; Ohta H.; Matsubayashi K.; Uwatoko Y.
Meeting Abstracts of the Physical Society of Japan, The Physical Society of Japan (JPS), 70, 1130-1130, 2015
Japanese - 23pBJ-9 Development and application of high pressure ESR system in THz region
Kawasaki K.; Matsui R.; Sakurai T.; Ohta H.; Okubo S.; Matsubayashi K.; Uwatoko Y.; Kudo K.; Koike Y.
Meeting Abstracts of the Physical Society of Japan, The Physical Society of Japan (JPS), 70, 1217-1217, 2015
Japanese - 19aDA-2 Single Crystal Growth and Valence Transition in EuPd_2Si_2 and EuPd_2Ge_2
Akamine H.; Ashitomi Y.; Amako Y.; Nakashima M.; Takeuchi T.; Matsubayashi K.; Uwatoko Y.; Honda F.; Hedo M.; Nakama T.; Onuki Y.
Meeting Abstracts of the Physical Society of Japan, The Physical Society of Japan (JPS), 70, 2075-2075, 2015
Japanese - 24pAB-8 Pressure effect on proton-electron correlated purely organic conductors, k-X_3(Cat-EDT-TTF)_2 (X=H, D)
Ueda A.; Yamada S.; Isono T.; Nakao A.; Kobayashi K.; Sagayama H.; Kumai R.; Nakao H.; Murakami Y.; Matsubayashi K.; Uwatoko Y.; Yoshizawa H.; Nishio Y.; Tajima N.; Kajita K.; Mori H.
Meeting Abstracts of the Physical Society of Japan, The Physical Society of Japan (JPS), 70, 1, 1921-1921, 2015
Japanese - 21aBC-9 Anomalous quantum transport in semi-metallic black phosphorus under multi-extreme conditions
Akiba K.; Miyake A.; Akahama Y.; Matsubayashi K.; Uwatoko Y.; Tokunaga M.
Meeting Abstracts of the Physical Society of Japan, The Physical Society of Japan (JPS), 70, 1965-1965, 2015
Japanese - 17aPS-62 Substitution effect of Zn site in a heavy fermion compound YbCo_2Zn_<20>
Takamura H.; Iwashita H.; Kakazu K.; Oooka T.; Higa Y.; Kobayashi R.; Aso N.; Matsubayashi K.; Uwatoko Y.
Meeting Abstracts of the Physical Society of Japan, The Physical Society of Japan (JPS), 70, 1857-1857, 2015
Japanese - 17aPS-60 Physical properties in a heavy fermion compound Yb(Co_<1-x>Ni_x)_2Zn_<20> III
Higa Y.; Kin K.; Sakai A.; Kobayashi R.; Aso N.; Matsubayashi K.; Uwatoko Y.
Meeting Abstracts of the Physical Society of Japan, The Physical Society of Japan (JPS), 70, 1855-1855, 2015
Japanese - 18pDA-3 Effect of pressure on antiferroquadrupolar order and superconductivity in PrV_2Al_<20>
Matsubayashi K.; Suzuki J.; Tsujimoto M.; Nakatsuji S.; Kitagawa K.; Uwatoko Y.
Meeting Abstracts of the Physical Society of Japan, The Physical Society of Japan (JPS), 70, 2024-2024, 2015
Japanese - 17aPS-33 Study of c-f mixing in CeX_c(X_c=S, Se, Te) by electric resistivity under pressure and magnetic field
Hayashi Y.; Takai S.; Matsumura T.; Sera M.; Matsubayashi K.; Uwatoko Y.; Ochiai A.
Meeting Abstracts of the Physical Society of Japan, The Physical Society of Japan (JPS), 70, 1828-1828, 2015
Japanese - 22pBA-6 Pressure effect of quantum criticality studied by ^<59>Co-NQR on Yb-124 compound
Kishimoto Y.; Kitagawa K.; Iwatani M.; Nishioka T.; Matsumura M.; Maki T.; Yamaura J.; Hattori T.; Ishida K.; Matsubayashi K.; Uwatoko Y.
Meeting Abstracts of the Physical Society of Japan, The Physical Society of Japan (JPS), 70, 2223-2223, 2015
Japanese - 22aPS-68 Physical properties in a heavy fermion compound Yb(Co_<1-x>Ni_x)_2Zn_<20> II
Higa Y.; Kin K.; Sakai A.; Kobayashi R.; Aso N.; Matsubayashi K.; Uwatoko Y.
Meeting Abstracts of the Physical Society of Japan, The Physical Society of Japan (JPS), 70, 2159-2159, 2015
Japanese - 22aPS-82 Quantum critical phenomenon and Ce valence estimation probed by X-ray absorption spectroscopy in Ce_2NiGa_<12>
Kawamura N.; Matsubayashi K.; Ishimatsu N.; Mizumaki M.; Uwatoko Y.; Ohara S.; Watanabe S.
Meeting Abstracts of the Physical Society of Japan, The Physical Society of Japan (JPS), 70, 2173-2173, 2015
Japanese - 22aPS-69 Effect of pressure on YbCo_2Ge_4 with a new 124 Structure
Matsubayashi K.; Iwatani M.; Kitagawa K.; Kawamura N.; Mizumaki M.; Ishimatsu N.; Watanabe S.; Uwatoko Y.
Meeting Abstracts of the Physical Society of Japan, The Physical Society of Japan (JPS), 70, 2160-2160, 2015
Japanese - 22pBC-15 Effect of pressure on the ferromagnetic compound MnP
CHENG J.-G.; MATSUBAYASHI K.; OKADA T.; UWATOKO Y.; WU W.; SUN J. P.; LIN F. K.; LUO J. L.; MATSUDA M.
Meeting Abstracts of the Physical Society of Japan, The Physical Society of Japan (JPS), 70, 2249-2249, 2015
Japanese - 21aPS-69 Magnetic Property and Pressure Effect of Mn_<2-x>Ni_<1+x>Ga
Yoshimine Y.; Mitsui Y.; Hiroi M.; Matsubayashi K.; Uwatoko Y.; Umetsu R.; Koyama K.
Meeting Abstracts of the Physical Society of Japan, The Physical Society of Japan (JPS), 70, 1003-1003, 2015
Japanese - Pressure Effect on the Martensitic Transformation and Magnetic Properties of Mn (2-x) Ni (1+ x) Ga
Mitsui, Yoshifuru; Yoshimine, Yuki; Umetsu, Rie; Matsubayashi, Kazuyuki; Uwatoko, Yoshiya; Hiroi, Masahiko; Koyama; Keiichi and
title Reports of the Faculty of Science, Kagoshima University 鹿児島大学理学部紀要, 48, 35-35, 2015
Scientific journal, English - Development of multi-frequency ESR system for high-pressure measurements up to 2.5 GPa
SAKURAI Takahiro; FUJIMOTO K; MATSUI Ryosuke; KAWASAKI Kohei; OKUBO Susumu; OHTA Hitoshi; MATSUBAYASHI Kazuyuki; UWAtOKO Yoshiya; YANAKA H
J. Mag. Res., 259, 108-113, 2015, Peer-reviwed, A new piston-cylinder pressure cell for electron spin resonance (ESR) has been developed. The pressure cell consists of a double-layer hybrid-type cylinder with internal components made of the ZrO2 -based ceramics. It can generate a pressure of 2 GPa repeatedly and reaches a maximum pressure of around 2.5 GPa. A high-pressure ESR system using a cryogen-free superconducting magnet up 10 T has also been developed for this hybrid-type pressure cell. The frequency region is from 50 GHz to 400 GHz. This is the first time a pressure above 2 GPa has been achieved in multi-frequency ESR system using a piston-cylinder pressure cell. We demonstrate its potential by showing the results of the high-pressure ESR of the S=1 system with the single ion anisotropy NiSnCl6 · 6H2 O and the S=1/2 quantum spin system CsCuCl3 . We performed ESR measurements of these systems above 2 GPa successfully.
Scientific journal, English - Anomalous pressure dependence of the superconductivity in noncentrosymmetric LaNiC2: Evidence of strong electronic correlations
Susumu Katano; Hideya Nakagawa; Kazuyuki Matsubayashi; Yoshiya Uwatoko; Hideto Soeda; Takahiro Tomita; Hiroki Takahashi
PHYSICAL REVIEW B, AMER PHYSICAL SOC, 90, 22, Dec. 2014, Peer-reviwed, The superconductivity of the noncentrosymmetric system LaNiC2 has been studied under high pressures up to 30 GPa with electrical resistivity measurements. For this superconducting state, the breaking of time-reversal symmetry was shown recently in a muon spin relaxation (mu SR) experiment, which leads to nonunitary spin-triplet superconductive pairings. The present experiments on this superconductor reveal that the transition temperature T-c greatly increases at the rate of 0.25 (+/- 0.01) K/GPa up to 3 GPa. However, above this pressure, T-c gradually decreases; and at the pressures over 8 GPa, the superconductivity disappears completely. With this disappearance of the superconductivity, a different state with a high-energy scale dramatically emerges. These results indicate that the system is not a simple normal metal, but is rather highly correlated with strong electronic interactions which would contribute to its superconductivity.
Scientific journal, English - Superconductivity in the vicinity of antiferromagnetic order in CrAs
Wei Wu; Jinguang Cheng; Kazuyuki Matsubayashi; Panpan Kong; Fukun Lin; Changqing Jin; Nanlin Wang; Yoshiya Uwatoko; Jianlin Luo
NATURE COMMUNICATIONS, NATURE PUBLISHING GROUP, 5, 83-87, Nov. 2014, Peer-reviwed, True, One of the common features of unconventional superconducting systems such as the heavy-fermion, high transition-temperature cuprate and iron-pnictide superconductors is that the superconductivity emerges in the vicinity of long-range antiferromagnetically ordered state. In addition to doping charge carriers, the application of external pressure is an effective and clean approach to induce unconventional superconductivity near a magnetic quantum critical point. Here we report on the discovery of superconductivity on the verge of antiferromagnetic order in CrAs via the application of external pressure. Bulk superconductivity with T-c approximate to 2 K emerges at the critical pressure P-c approximate to 8 kbar, where the first-order antiferromagnetic transition at T-N approximate to 265 K under ambient pressure is completely suppressed. The close proximity of superconductivity to an antiferromagnetic order suggests an unconventional pairing mechanism for CrAs. The present finding opens a new avenue for searching novel superconductors in the Cr and other transition metal-based systems.
Scientific journal, English - Integrated-fin gasket for palm cubic-anvil high pressure apparatus
J. G. Cheng; K. Matsubayashi; S. Nagasaki; A. Hisada; T. Hirayama; M. Hedo; H. Kagi; Y. Uwatoko
Review of Scientific Instruments, American Institute of Physics Inc., 85, 9, 01 Sep. 2014, Peer-reviwed, We described an integrated-fin gasket technique for the palm cubic-anvil apparatus specialized for the high-pressure and low-temperature measurements. By using such a gasket made from the semi-sintered MgO ceramics and the tungsten-carbide anvils of 2.5 mm square top, we successfully generate pressures over 16 GPa at both room and cryogenic temperatures down to 0.5 K. We observed a pressure self-increment for this specific configuration and further characterized the thermally induced pressure variation by monitoring the antiferromagnetic transition temperature of chromium up to 12 GPa. In addition to enlarge the pressure capacity, such a modified gasket also improves greatly the surviving rate of electrical leads hanging the sample inside a Teflon capsule filled with the liquid pressure-transmitting medium. These improvements should be attributed to the reduced extrusion of gasket materials during the initial compression.
Scientific journal, English - Superconductivity in the topological insulator Bi2Te3 under hydrostatic pressure
K. Matsubayashi; T. Terai; J. S. Zhou; Y. Uwatoko
PHYSICAL REVIEW B, AMER PHYSICAL SOC, 90, 12, Sep. 2014, Peer-reviwed, We report the resistivity and ac susceptibility measurements of the topological insulator Bi2Te3 single crystals at pressures up to 11 GPa. Under highly hydrostatic pressure conditions generated in a multi-anvil high-pressure apparatus, a pressure-induced superconductivity only appears above a critical pressure PC similar to 7 GPa, coinciding with a structural transition from a rhombohedral to a monoclinic structure. The absence of superconductivity in the rhombohedral phase at pressures below PC, which is contrary to previous studies using the high-pressure apparatus with a solid pressure medium, suggests that the occurrence of superconductivity in the rhombohedral phase is sensitive to pressure conditions such as pressure inhomogeneity or uniaxial stress.
Scientific journal, English - Doping- and pressure-induced change of electrical and magnetic properties in the Fe-based spin-ladder compound BaFe2Se3
Fei Du; Yasuyuki Hirata; Kazuyuki Matsubayashi; Yoshiya Uwatoko; Yutaka Ueda; Kenya Ohgushi
PHYSICAL REVIEW B, AMER PHYSICAL SOC, 90, 8, Aug. 2014, Peer-reviwed, We have investigated the evolution of electronic structure in the Fe-based ladder compound Ba(Fe1-xCox)(2)Se-3 (0 <= x <= 0.15) by means of resistivity, magnetic susceptibility, and reflectivity measurements. Although the Co substitution into BaFe2Se3 greatly decreases the resistivity, the compound still shows an insulating behavior at x = 0.15. Moreover, the insulating state at x = 0.15 is robust even under the high pressure of 8 GPa. The antiferromagnetic transition temperatures are gradually suppressed by substituting Co atoms at x <= 0.10, while the spin glass state is observed at x >= 0.125. Our finding revealed that the substituted Co atoms play a dual effect: electron-carrier dopant and localized moment, providing a supplemental insight into the doping effect in the Fe-based superconductors.
Scientific journal, English - Superconductivity on a Crossover Phenomenon of Spin-Ladder System SrCa13Cu24O41 Single Crystals
Akihiko Hisada; Kazuyuki Matsubayashi; Yoshiya Uwatoko; Naoki Fujiwara; Guochu Deng; Ekaterina Pomjakushina; Kazimierz Conder; Dinadhayalane Mohan Radheep; Raman Thiyagarajan; Sankaran Esakkimuthu; Sonachalam Arumugam
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, PHYSICAL SOC JAPAN, 83, 7, 073703-1-073703-4, Jul. 2014, Peer-reviwed, Electrical resistivity and alternating current susceptibility measurements were performed for the spin-ladder compound SrCa13Cu24O41 under hydrostatic pressure up to 8 GPa. The superconducting transition was observed below T-C = 14.7K at pressures above 2 GPa. By using high-quality single crystals, the bulk superconductivity with a volume fraction of 50% and temperature quadratic behavior of the normal state resistivity were observed above 3.7 GPa. They suggest that a strong interladder interaction induces the bulk superconductivity and transforms the system into a Fermiliquid- like state. The optimal pressure was in a crossover region and the highest T-C was observed without going through the bulk superconducting state. Our results suggest that the superconducting state on the crossover phenomenon presents the feature of the doped two-leg spin-ladder system because the spin gap was observed in this compound.
Scientific journal, English - Magnetic and Fermi Surface Properties of Antiferromagnet EuCd11
Ai Nakamura; Yuichi Hiranaka; Taro Uejo; Tetsuya Takeuchi; Fuminori Honda; Hisatomo Harima; Kazuyuki Matsubayashi; Yoshiya Uwatoko; Masato Hedo; Takao Nakama; Yoshichika Onuki
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, PHYSICAL SOC JAPAN, 83, 7, 074714, Jul. 2014, Peer-reviwed, We succeeded in growing a high-quality single crystal of EuCd11 with the BaCd11-type tetragonal structure by the Cd self-flux method, and measured the electrical resistivity, specific heat, magnetic susceptibility, magnetization, and de Haas-van Alphen (dHvA) oscillations, together with the electrical resistivity under high pressures up to 8 GPa. The antiferromagnetic ordering was confirmed to occur at the Neel temperature T-N = 2.7 K, and the antiferromagnetic state was found to change into the field-induced ferromagnetic state with 7 mu B/Eu above a critical field H-c similar or equal to 15 kOe for both the magnetic fields H parallel to [100] and [001], revealing a typical Eu-divalent antiferromagnet. Reflecting the large lattice parameters of a = 11.93 angstrom and c = 7.682 angstrom with the caged structure, where each Eu atom is surrounded by a polyhedron of 22 Cd atoms, the Brillouin zone and the corresponding Fermi surfaces are small in volume. The detected dHvA branches are well explained by the full potential linear augmented plane wave (FLAPW) energy band calculations for the non-4f reference compound SrCd11, revealing ellipsoidal Fermi surfaces with complicated concave and convex shapes. The present Eu-divalent electronic state is found to be robust against high pressures up to 8 GPa, and does not change into the Eu-trivalent state.
Scientific journal, English - Drastic Change of Electronic Properties in Ce2MgSi2 and CeNiIn4 under High Pressure
Fuminori Honda; Naohisa Yoshitani; Yusuke Hirose; Kazuhiro Ishida; Takashi Maeta; Atsushi Miyake; Shigeki Tanaka; Katsuya Shimizu; Tetsuya Takeuchi; Kazuyuki Matsubayashi; Yoshiya Uwatoko; Rikio Settai; Dai Aoki; Yoshichika Onuki
JPS Conference Proceedings, Proceedings of the International Conference on Strongly Correlated Electron Systems (SCES2013), 3, 011082-1-011082-6, 16 Jun. 2014, Peer-reviwed
Scientific journal, English - High-pressure effects in anti-post-perovskite superconductors V(3)PnN(x) (Pn = P, As)
B. S. Wang; J. -G. Cheng; K. Matsubayashi; Y. Uwatoko; K. Ohgushi
PHYSICAL REVIEW B, AMER PHYSICAL SOC, 89, 14, Apr. 2014, Peer-reviwed, Pressure effects on the superconductors V(3)PnN(x) (Pn = P and As) with the two-dimensional anti-post-perovskite structure were investigated. It was found that with increasing pressure, the superconducting transition temperature (T-c) decreases with a negative differential pressure ( P) coefficient dT(c)/dP = - 0.19 and -0.013 K/GPa for Pn = P and As, respectively. This is in marked contrast to the positive differential pressure coefficients reported for other vanadium-based superconductors with a three-dimensional crystal structure. The observed change in Tc under pressure is revealed to be closely correlated with the evolution of the normal-state resistivity. The results support the phonon-mediated superconductivity in V(3)PnN(x).
Scientific journal, English - Long-range antiferromagnetic order in the frustrated XY pyrochlore antiferromagnet Er2Ge2O7
X. Li; W. M. Li; K. Matsubayashi; Y. Sato; C. Q. Jin; Y. Uwatoko; T. Kawae; A. M. Hallas; C. R. Wiebe; A. M. Arevalo-Lopez; J. P. Attfield; J. S. Gardner; R. S. Freitas; H. D. Zhou; J. G. Cheng
PHYSICAL REVIEW B, AMER PHYSICAL SOC, 89, 6, 728-729, Feb. 2014, Peer-reviwed, A cubic Er2Ge2O7 pyrochlore was prepared under high-pressure and high-temperature conditions and its magnetic ground state was investigated by measurements of specific heat, dc and ac magnetic susceptibility as functions of temperature, pressure, and magnetic field. We found that Er2Ge2O7 undergoes a long-range antiferromagnetic transition at T-N approximate to 1.4 K, which can be further enhanced by applying external physical pressure. On the other hand, application of external magnetic fields suppresses the antiferromagnetic order to zero temperature around H-c approximate to 2.3 T, where a magnetic-field-induced spin-flop transition was observed. H-c increases accordinglywith increasing T-N under external pressure. Acomparison of the magnetic ground states and structural variations along the isostructural series Er2B2O7 (B = Sn, Ti, Ge) together with the high-pressure study on Er2Ge2O7 indicated that the magnetic properties of these highly frustrated XY pyrochlore antiferromagnets are very sensitive to the minute structural changes that determine the anisotropic exchange interactions and the local crystal-electric-field environments of Er3+ ions.
Scientific journal, English - Long-range antiferromagnetic order in the frustrated XY pyrochlore antiferromagnet Er 2 Ge 2 O 7
Li, X.; Li, WM; Matsubayashi, K.; Sato, Y.; Jin, CQ; Uwatoko, Y.; Kawae, T.; Hallas, AM; Wiebe, CR; Arevalo-Lopez, AM
Physical Review B, American Physical Society, 89, 6, 064409-064409, 2014
Scientific journal - Heavy Fermion Superconductivity under Pressure in the Quadrupole System PrTi2Al20
Kazuyuki Matsubayashi; Toshiki Tanaka; Junichirou Suzuki; Akito Sakai; Satoru Nakatsuji; Kentaro Kitagawa; Yasunori Kubo; Yoshiya Uwatoko
Proceedings of the International Conference on Strongly Correlated Electron Systems (SCES2013), 11077, 2014, Peer-reviwed - Magnetic and transport properties of EuNi(Si1-xGex)(3) compounds
K. Uchima; Y. Takaesu; H. Akamine; M. Kakihana; K. Tomori; T. Uejo; A. Teruya; A. Nakamura; M. Hedo; T. Nakama; K. Yagasaki; K. Matsubayashi; Y. Uwatoko
27TH INTERNATIONAL CONFERENCE ON LOW TEMPERATURE PHYSICS (LT27), PTS 1-5, IOP PUBLISHING LTD, 568, 2014, Peer-reviwed, The magnetization M, electrical resistivity rho, thermopower S and specific heat C of EuNi(Si1-xGex)(3) compounds have been measured at temperatures from 2 to 300 K. For the compounds of EuNi(Si1-xGex)(3), we obtained an effective magnetic moment of mu(eff) approximate to 7.7 mu(B), which is close to the divalent Eu value of mu(eff) = 7.94 mu(B). All compounds of EuNi(Si1-xGex)(3) order antiferromagnetically. The Neel temperature T-N decreases monotonously with increasing the Ge concentration x from T-N=49 K for EuNiSi3 to T-N=14 K for EuNiGe3. In the low temperature region below T-N, anomalies corresponding to an additional magnetic phase transition into ferromagnetic state for compounds with x < 0.3, and into another antiferromagnetic for x > 0.3 were observed. The Curie temperature T-C rapidly decreases with increasing x and vanishes at x approximate to 0.3. It is found that the magnetic phase transition temperatures of T-N and T-C in EuNi(Si1-xGex)(3) are strongly connected with the change of volume induced by the atomic substitution of Si by Ge.
International conference proceedings, English - Heavy Fermion State in EuNi2P2 under Pressure
Hiranaka, Yuichi; Nakamura, Ai; Hedo, Masato; Takeuchi, Tetsuya; Matsubayashi, Kazuyuki; Uwatoko, Yoshiya; Nakama, Takao; Ōnuki, Yoshichika
JPS Conf. Proc., 2014, Peer-reviwed
International conference proceedings, English - Magnetic Field Effect on Magnetic and Electrical Properties of Mn2-xCuxSb
Yoshihiro Matsumoto; Hiroki Orihashi; Kazuyuki Matsubayashi; Yoshiya Uwatoko; Masahiko Hiroi; Keiichi Koyama
IEEE TRANSACTIONS ON MAGNETICS, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 50, 1, 747-750, Jan. 2014, Peer-reviwed, In order to investigate the magnetic and the electrical properties of Mn2-xCuxSb (x=0.06, 0.10, and 0.15), the magnetization and the electrical resistivity measurements were carried out in the temperature range from 10 K to 300 K under magnetic fields up to mu(0) H = 5 T. The Curie temperature T-C of Mn1.94Cu0.06Sb was determined to be 517 K. Mn1.94Cu0.06Sb showed a first-order magnetic transition from a ferrimagnetic (FRI) to an antiferromagnetic (AFM) phase at T-t = 117 K with a thermal hysteresis of approximately 20 K. The low-field magnetic data of Mn1.94Cu0.06Sb also showed an anomaly at 207 K, indicating a spin reorientation. With increasing x, T-t increases to 154 K (x = 0.15), whereas T-C is almost constant for 0.06 <= x <= 0.15. The electrical resistivity changes abruptly by 25%-36% at T-t. By applying a magnetic field of mu(0) H = 5 T, T-t decreases and the width of the hysteresis increases. In addition, we confirmed that the value of the magnetization at low temperatures below T-t depends on the cooling process for a magnetic field.
Scientific journal, English - High Pressure Properties for Electrical Resistivity and Ce Valence State of Heavy-Fermion Antiferromagnet Ce2NiGa12
N. Kawamura; R. Sasaki; K. Matsubayashi; N. Ishimatsu; M. Mizumaki; Y. Uwatoko; S. Ohara; S. Watanabe
27TH INTERNATIONAL CONFERENCE ON LOW TEMPERATURE PHYSICS (LT27), PTS 1-5, IOP PUBLISHING LTD, 568, 1007-1012, 2014, Peer-reviwed, A heavy-fermion antiferromagnet Ce(2)NiGai(2) has been studied at a viewpoint of pressure effects. Electrical resistivity measurements show that the antiferromagnetic ordering is suppressed at P-C similar to 5.5 GPa, and that Fermi liquid behaviour is observed above P-C. To investigate how Ce valence state is associated with the observed critical phenomena, X-ray absorption spectra at Ce L-3-edge have been performed. Ce valence state drastically varies at P-v similar to 9 GPa in the initial applying pressure process, whereas anomalous behaviour is not observed in the Ce valence under pressures around P-C. Consequently, the quantum critical phenomena in Ce(2)NiGai(2) around P-C is not strongly connected with Ce valence state.
International conference proceedings, English - Development of non-metallic diamond anvil cell and quantum oscillation measurement of CePt
2 ln7 in a pulsed-magnet
Atsushi Miyake; Yoshimitsu Kohama; Shunpei Ohta; Yusuke Hirose; Rikio Settai; Kazuyuki Matsubayashi; Yoshiya Uwatoko; Akira Matsuo; Koichi Kindo; Masashi Tokunaga
Journal of Physics: Conference Series, 592, 1, 1670-1674, 2014, Peer-reviwed, In order to combine the extreme conditions of high pressure and magnetic field, we have developed a non-metallic diamond anvil cell to avoid Joule-heating in a pulsed-magnetic field. Although the cell is deformed with loading, a maximum pressure of ∼ 8.5 GPa can be applied. Quantum oscillation measurements using tunnel diode oscillator have been performed for heavy fermion antiferromagnet CePt2In7 in a pulsed field and at ambient pressure. The detail of the pressure cell and field-induced Fermi surface changes of CePt2In7 are discussed.
International conference proceedings, English - Fermi surface and magnetic properties of antiferromagnet EuBi
3
Ai Nakamura; Yuichi Hiranaka; Masato Hedo; Takao Nakama; Yasutomi Tatetsu; Takahiro Maehira; Yasunao Miura; Akinobu Mori; Hiroki Tsutsumi; Yusuke Hirose; Katsuya Mitamura; Kiyohiro Sugiyama; Masayuki Hagiwara; Fuminori Honda; Tetsuya Takeuchi; Yoshinori Haga; Kazuyuki Matsubayashi; Yoshiya Uwatoko; Yoshichika Onuki
Journal of the Physical Society of Japan, 82, 12, 2097-2102, Dec. 2013, Peer-reviwed, EuBi3 with the AuCu3-type cubic structure is known to be a Eu-divalent antiferromagnet with the Néel temperature TN ∼ 7:5 K. We succeeded in growing a high-quality single crystal by the Bi self-flux method. The magnetization at 1.3K for the magnetic field along the h100i direction increases linearly as a function of magnetic field, and saturates at a critical field Hc = 225 kOe, reaching a saturated magnetic moment of 7μB/Eu. Hc is well explained by the magnetic exchange interaction based on a two-sublattice model, using the simple relation Hc = (kB/3μB)(TN- θp) namely, Hc [kOe= 4:9 (TN - θp) [K], where θp is the paramagnetic Curie temperature θp = -36 K. The present antiferromagnetic state is found to be stable under pressures up to 8 GPa, where the Néel temperature increases with increasing pressure, being TN = 16:5K at 8 GPa. From the results of de Haas-van Alphen experiments on EuBiT3 and energy band calculations for the non-4f reference compound SrBi3, the Fermi surface is found to consist of three types of nearly spherical Fermi surfaces. © 2013 The Physical Society of Japan.
Scientific journal, English - High-pressure synthesis of the BaIrO3 perovskite: A Pauli paramagnetic metal with a Fermi liquid ground state
J-G Cheng; T. Ishii; H. Kojitani; K. Matsubayashi; A. Matsuo; X. Li; Y. Shirako; J-S Zhou; J. B. Goodenough; C. Q. Jin; M. Akaogi; Y. Uwatoko
PHYSICAL REVIEW B, AMER PHYSICAL SOC, 88, 20, 2097-2102, Nov. 2013, Peer-reviwed, BaIrO3 adopts the 9R polytype structure if it is synthesized at ambient pressure. High-pressure and high-temperature treatments up to 10 GPa have led to other 5H and 6H polytype phases, which are quenchable to the ambient condition. However, the single-phase 3C perovskite, the end member of polytypes, has not been obtained so far. Here we report the high-pressure synthesis of BaIrO3 perovskite under 25 GPa and 1150 degrees C. Rietveld refinement on the powder x-ray diffraction pattern revealed that this new compound crystallizes in a tetragonal I4/mcm structure rather than the expected cubic Pm-3m structure. The new perovskite is a Pauli paramagnetic metal with a Fermi liquid ground state, i.e., rho proportional to T-2 below 6 K. The availability of BaIrO3 perovskite also allows completion of the structure-physical property evolution in the AIrO(3) perovskites (A = Ca, Sr, Ba). The Fermi energy located in bands originated from Ir: 5d and O: 2p electrons are found to be very sensitive to the change of crystal structure.
Scientific journal, English - Pressure Effect on the Structure and Superconducting Transition Temperature of Filled Skutterudites LaT4P12 (T = Fe, Ru)
Yukihiro Kawamura; Takuma Kawaai; Junichi Hayashi; Chihiro Sekine; Hirotada Gotou; Jinguang Cheng; Kazuyuki Matsubayashi; Yoshiya Uwatoko
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, PHYSICAL SOC JAPAN, 82, 11, 893-898, Nov. 2013, Peer-reviwed, We studied the effect of pressure on the superconducting transition temperature T-SC of LaT4P12 ( T = Fe, Ru) up to 8 GPa through electrical resistivity measurements in a cubic anvil apparatus. The T-SC of LaFe4P12 was also determined through magnetization measurements up to 3.4 GPa with an opposed-anvil pressure cell. In LaFe4P12, T-SC increases with pressure at a rate of 0.71 K/GPa from 0 GPa reaching its maximum at approximately 7 GPa. In contrast, the T-SC of LaRu4P12 monotonically decreases with pressure. The decrease rate gradually increases from -0.07 to -0.29 K/GPa. The distinct pressure dependences of both T-SC's cannot be explained solely from a structural point of view. We propose that the difference between the pressure dependence of T-SC for LaFe4P12 and that for LaRu4P12 can be attributed to the difference in the electronic density of states at the Fermi energy between these two compounds.
Scientific journal, English - Magnetic penetration depth and flux-flow resistivity measurements on NaFe0.97Co0.03As single crystals
T. Okada; H. Takahashi; Y. Imai; K. Kitagawa; K. Matsubayashi; Y. Uwatoko; A. Maeda
PHYSICA C-SUPERCONDUCTIVITY AND ITS APPLICATIONS, ELSEVIER SCIENCE BV, 494, 109-112, Nov. 2013, Peer-reviwed, We measured the surface impedance of NaFe1-xCoxAs (x approximate to 0.03, optimally doped) single crystals under finite magnetic fields. At low temperatures (T < 0.5T(c)), the penetration depth of these crystals was increased as lambda(T) - lambda(0) = A x T-n with an exponent n approximate to 2, indicating the realization of the gapless superconductivity. The flux-flow resistivity, rho(f), behaved similarly to the Bardeen- Stephen prediction, rho(f)/rho(n) = B/B-c2. However, the electronic state inside the vortex core was not so dirty. By comparing the results with those of LiFeAs1-xPx and SrFe2(As0.7P0.3)(2), it has been clarified that the gap anisotropy dominates the gradient of rho(f)(B). (c) 2013 Elsevier B.V. All rights reserved.
Scientific journal, English - Possible kondo physics near a metal-insulator crossover in the a-site ordered perovskite CaCu3Ir4O12
J. G. Cheng; J. S. Zhou; Y. F. Yang; H. D. Zhou; K. Matsubayashi; Y. Uwatoko; A. Macdonald; J. B. Goodenough
Physical Review Letters, 111, 17, 23 Oct. 2013, Peer-reviwed, The A-site ordered perovskite (AA3′)B4O12 can accommodate transition metals on both A′ and B sites in the crystal structure. Because of this structural feature, it is possible to have narrow-band electrons interacting with broadband electrons from different sublattices. Here we report a new A-site ordered perovskite (CaCu 3)Ir4O12 synthesized under high pressure. The coupling between localized spins on Cu2+ and itinerant electrons from the Ir-O sublattice makes Kondo-like physics take place at a temperature as high as 80 K. Results from the local density approximation calculation have confirmed the relevant band structure. The magnetization anomaly found at 80 K can be well rationalized by the two-fluid model. © 2013 American Physical Society.
Scientific journal, English - Development of a Low-Temperature Insert for Precise Magnetization Measurement below T=2K with a Superconducting Quantum Interference Device Magnetometer
Yoshiaki Sato; Shun Makiyama; Yasutaka Sakamoto; Tadahiko Hasuo; Yuji Inagaki; Tetsuya Fujiwara; Hiroyuki S. Suzuki; Kazuyuki Matsubayashi; Yoshiya Uwatoko; Tatsuya Kawae
JAPANESE JOURNAL OF APPLIED PHYSICS, IOP PUBLISHING LTD, 52, 10, Oct. 2013, Peer-reviwed, We have developed a 9-mm-diameter He-3 insert for precise magnetization measurements below T = 2 K that is attachable to a commercial superconducting quantum interference device magnetometer. The insert is made from a thin-walled stainless steel pipe with an inner diameter of 6.2 mm, which determines the maximum sample size. He-3 gas is condensed in the pipe, which is liquefied by He-4 gas at T similar to 1.8 K generated by the magnetometer via the heat exchanger of a Cu vacuum jacket with an outer diameter of 8.6mm soldered to the stainless steel pipe. The temperature of the insert is decreased to T similar to 0.5 K by evacuating liquid 3He using a rotary pump and then to T = 0.36 K with a sorption pump. From the diamagnetization signal of a superconducting Al chip with a mass below 0.1 mg, the magnetization resolution with the insert is confirmed to be less than 10(-7) emu. To examine the performance of the insert, we measured the temperature dependence of the magnetic susceptibility and magnetization for Pr0.6La0.4Ag2In down to T = 0.4 K. (C) 2013 The Japan Society of Applied Physics
Scientific journal, English - Microscopic evidence of a crossover to a low-temperature intermediate valence state in YbCo2Zn20
Takeshi Mito; Hiroki Hara; Takuma Ishida; Keitaro Nakagawara; Takehide Koyama; Koichi Ueda; Takao Kohara; Kenji Ishida; Kazuyuki Matsubayashi; Yuta Saiga; Yoshiya Uwatoko
Journal of the Physical Society of Japan, 82, 10, Oct. 2013, Peer-reviwed, The low-temperature properties of YbCo2Zn20, which shows a giant specific heat at low temperatures, have been studied by the 59Co-nuclear quadrupole resonance (NQR) technique. The measurement of spin lattice relaxation rate reveals that Yb 4f-electrons unusually persist in a well-localized regime down to at least 0.3K without ordering magnetically. With further lowering temperature, NQR frequency decreases below 0.2K reflecting the lowtemperature Fermi liquid state, even suggesting a crossover to an intermediate valence state in close proximity to the localized-delocalzied transition. We also compare the observed unique properties of YbCo 2Zn20 with those of YbRh2Si2, which shows antiferromagnetic ordering at extremely low temperature. © 2013 The Physical Society of Japan.
Scientific journal, English - Magnetic and fermi surface properties of EuGa
4
Ai Nakamura; Yuichi Hiranaka; Masato Hedo; Takao Nakama; Yasunao Miura; Hiroki Tsutsumi; Akinobu Mori; Kazuhiro Ishida; Katsuya Mitamura; Yusuke Hirose; Kiyohiro Sugiyama; Fuminori Honda; Rikio Settai; Tetsuya Takeuchi; Masayuki Hagiwara; Tatsuma D. Matsuda; Etsuji Yamamoto; Yoshinori Haga; Kazuyuki Matsubayashi; Yoshiya Uwatoko; Hisatomo Harima; Yoshichika Onuki
Journal of the Physical Society of Japan, 82, 10, 893-898, Oct. 2013, Peer-reviwed, We grew a high-quality single crystal EuGa4 with the tetragonal structure by the Ga self-flux method, and measured the electrical resistivity, magnetic susceptibility, high-field magnetization, specific heat, thermoelectric power and de Haas-van Alphen (dHvA) effect, together with the electrical resistivity and thermoelectric power under pressure. EuGa4 is found to be a Eu-divalent compound without anisotropy of the magnetic susceptibility in the paramagnetic state and to reveal the same magnetization curve between H ∥ [100] and [001] in the antiferromagnetic state, where the antiferromagnetic easy-axis is oriented along the [100] direction below a Néel temperature TN = 16:5 K. The magnetization curve is discussed on the basis of a simple two-sublattice model. The Fermi surface in the paramagnetic state was clarified from the results of a dHvA experiment for EuGa4 and an energy band calculation for a non-4f reference compound SrGa4, which consists of a small ellipsoidal hole-Fermi surface and a compensated cube-like electron-Fermi surface with vacant space in center. We observed an anomaly in the temperature dependence of the electrical resistivity and thermoelectric power at TCDW = 150K under 2 GPa. This might correspond to an emergence of the charge density wave (CDW). The similar phenomenon was also observed in EuAl4 at ambient pressure. We discussed the CDW phenomenon on the basis of the present peculiar Fermi surfaces. © 2013 The Physical Society of Japan.
Scientific journal, English - Hydrostatic pressure (8 GPa) dependence of electrical resistivity of BaCo2As2 single crystal
Chandreyee Ganguli; Kazuyuki Matsubayashi; Kenya Ohgushi; Yoshiya Uwatoko; Moorthi Kanagaraj; Sonachalam Arumugam
MATERIALS RESEARCH BULLETIN, PERGAMON-ELSEVIER SCIENCE LTD, 48, 10, 4329-4331, Oct. 2013, Peer-reviwed, The pressure pressure dependence of the electrical resistivity of BaCo2As2 single crystal as a function of temperature was measured at ambient and high pressures up to 8 GPa for the first time using cubic anvil high pressure cell. It is observed that at room temperature the resistivity monotonically decreases with increasing pressure and it remains in the metallic state even at an applied pressure of 8 GPa. From the temperature dependence of the resistivity measurements under pressure, we found that superconductivity is absent up to 8 GPa. The value of the electron's scattering factor (A) is found to be large at ambient pressure and it decreases with the application of pressure, indicating that the substantial electron correlation effect of BaCo2As2 is reduced under pressure, revealing a dramatic change of density of states at the Fermi energy. (C) 2013 Elsevier Ltd. All rights reserved.
Scientific journal, English - AC susceptibility of the dipolar spin ice Dy2Ti 2O7: Experiments and Monte Carlo simulations
Hiroshi Takatsu; Kazuki Goto; Hiromi Otsuka; Ryuji Higashinaka; Kazuyuki Matsubayashi; Yoshiya Uwatoko; Hiroaki Kadowaki
Journal of the Physical Society of Japan, 82, 10, 4329-4331, Oct. 2013, Peer-reviwed, Experimental data of the frequency-dependent ac susceptibility [χac(ω)] for the dipolar spin ice Dy2Ti 2O7 has been analyzed by Monte Carlo simulations on the basis of the single-spin-flip Metropolis algorithm. We have directly evaluated χac(ω) by applying an ac magnetic field. We found that this simulation reasonably reproduces the experimental behavior of χac(Omega
) in the temperature range from 0.6 to 1.0 K, where dilute magnetic monopoles diffusively move. The conversion factor from simulation time to real time, i.e., the rate of hopping of monopoles to nearest-neighbor sites, strongly depends on temperature. © 2013 The Physical Society of Japan.
Scientific journal, English - Change in Unusual Magnetic Properties by Rh Substitution in CeRu2Al10
Riki Kobayashi; Yuta Ogane; Daishi Hirai; Takashi Nishioka; Masahiro Matsumura; Yukihiro Kawamura; Kazuyuki Matsubayashi; Yoshiya Uwatoko; Hiroshi Tanida; Masafumi Sera
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, PHYSICAL SOC JAPAN, 82, 9, 29-33, Sep. 2013, Peer-reviwed, We have studied the Rh substitution (electron doping) effect in the Kondo semiconductor CeRu2Al10, which orders antiferromagnetically below (T-0 = 27 K), by specific heat C, magnetic susceptibility chi, electrical resistivity rho, and Hall resistivity rho(H) measurements of Ce(Ru1-xRhx)(2)Al-10 (x = 0: 12, 0.2, 0.23, 0.34) single crystals. T-0 decreases monotonically with an increase in x. In addition, new anomalies occur at T-1 similar to 6.5 and T-2 similar to 3.0 K in all the Rh substitution samples. However, T-1 and T-2 are almost independent of x. The shape of the anomaly at T-0 in chi(T) changes with Rh substitution, which implies the reorientation of the ordered moment. These phenomena indicate that the magnetic properties of CeRu2Al10 are strongly associated with the number of 4d electrons.
Scientific journal, English - Successive magnetic transitions of PrRh2 single crystals
Yu Okawara; Jingwei Cui; Tetsuya Fujiwara; Toru Shigeoka; Kazuyuki Matsubayashi; Yoshiya Uwatoko; Shojiro Kimura; Kazuo Watanabe
JOURNAL OF THE KOREAN PHYSICAL SOCIETY, KOREAN PHYSICAL SOC, 63, 3, 743-746, Aug. 2013, Peer-reviwed, Measurements of the magnetization and the specific heat were performed on a PrRh2 single crystal. A strong magnetic anisotropy with the easy magnetization direction of the c-axis is observed. Four anomalies appear in the temperature dependence of magnetic susceptibility along the c-axis; a cusp at T (N) =52 K, a high peak at T (3)=38 K, a shoulder at T (2)=33 K and a small peak at T (1)=4 K are observed, indicating magnetic transitions. The specific heat also shows four anomalies at the temperatures where the magnetic anomalies appear, confirming the occurrence of successive magnetic transitions. A clear two-step metamagnetic process appears along the easy magnetization direction of the c-axis at low temperatures. The magnetization in the first step is almost constant and is corresponds to (1/5) M (s) (M (s) : saturation magnetization), indicating that this field-induced phase has a long period and a stable magnetic structure. A metamagnetic process is hypothesized on the basis of the magnetic structure. The B (001) - T phase diagram is constructed.
Scientific journal, English - Development of Hybrid-Type Pressure Cell for High-Pressure and High-Field ESR Measurement
Kohdai Fujimoto; Takahiro Sakurai; Susumu Okubo; Hitoshi Ohta; Kazuyuki Matsubayashi; Yoshiya Uwatoko; Kazutaka Kudo; Yoji Koike
Applied Magnetic Resonance, 44, 8, 893-898, Aug. 2013, Peer-reviwed, A hybrid-type piston-cylinder pressure cell for the electron spin resonance (ESR) measurement has been developed. The cylinder of this pressure cell consists of a NiCrAl inner cylinder and a CuBe outer sleeve, and all inner parts are made of zirconium oxide which has good transmittance to the millimeter and submillimeter waves. We confirmed that the pressure reaches 2.1 GPa. We have also developed a transmission-type high-field ESR system having two different modulation methods for this pressure cell. A test measurement without pressure cell for the two-dimensional orthogonal-dimer spin system of SrCu2(BO3)2 has been done successfully in the wide frequency region. The combination of this electromagnetic wave transmission-type pressure cell and this high-field ESR system is a promising tool for the study of the pressure-induced phase transition of SrCu2(BO3)2. © 2013 Springer-Verlag Wien.
Scientific journal, English - Magnetic properties of Mn2Sb1-x Ge (x) (0.05 a parts per thousand currency sign x a parts per thousand currency sign 0.2) in high magnetic fields
Daisuke Shimada; Hiroki Orihashi; Daisuke Mitsunaga; Masakazu Ito; Masahiko Hiroi; Keiichi Koyama; Reisho Onodera; Kohki Takahashi; Kazuyuki Matsubayashi; Yoshiya Uwatoko
JOURNAL OF THE KOREAN PHYSICAL SOCIETY, KOREAN PHYSICAL SOC, 63, 3, 747-750, Aug. 2013, Peer-reviwed, Magnetization and electrical resistivity measurements were carried out for polycrystalline Mn2Sb1-x Ge (x) (0.05 a parts per thousand currency sign x a parts per thousand currency sign 0.2) in magnetic fields up to 16 T in the 4.2 - 600 K temperature range in order to investigate the magnetic and the electrical properties under high magnetic fields. Mn2Sb0.92Ge0.08 showed a Curie temperature, T (C) , of 532 K and a first order magnetic transition from a ferrimagnetic (FRI) to an antiferromagnetic (AFM) phase at T (t) = 230 K with decreasing temperature in a zero magnetic field. With increasing x, T (C) decreased and T (t) increased. For Mn2Sb0.92Ge0.08, a matamagnetic transition from an AFM to a FRI phase was observed at 215 K. The magnetic phase diagram of Mn2Sb1-x Ge (x) is presented.
Scientific journal, English - Two-Dimensional Monopole Dynamics in the Dipolar Spin Ice Dy2Ti2O7
Hiroshi Takatsu; Kazuki Goto; Hiromi Otsuka; Ryuji Higashinaka; Kazuyuki Matsubayashi; Yoshiya Uwatoko; Hiroaki Kadowaki
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, PHYSICAL SOC JAPAN, 82, 7, 50-52, Jul. 2013, Peer-reviwed, The spin dynamics of the dipolar spin-ice Dy2Ti2O7 under a dc magnetic field (B-dc) along the [111] direction has been investigated using ac susceptibility (chi(ac)), which enables us to study two-dimensional monopole motion in an ac magnetic field perpendicular to Bdc. We have observed the slowing down of monopole dynamics in the kagome spin-ice regime (B-dc similar to 0.4 T) and the extreme speeding up under B-dc close to the critical point (B-dc similar to 0.93 T). An analysis using a Monte Carlo simulation suggests that the dynamics changes from a random walk of monopoles to a collective motion as B-dc increases.
Scientific journal, English - Pressure dependence of the superconducting transition temperature of the filled skutterudite YFe4P12
J. -G. Cheng; J. -S. Zhou; K. Matsubayashi; P. P. Kong; Y. Kubo; Y. Kawamura; C. Sekine; C. Q. Jin; J. B. Goodenough; Y. Uwatoko
PHYSICAL REVIEW B, AMER PHYSICAL SOC, 88, 2, 7069-7073, Jul. 2013, Peer-reviwed, We have studied the pressure dependence of the superconducting transition temperature T-c of the filled skutterudite YFe4P12 under various quasihydrostatic pressures up to 8 GPa. DC magnetization measurements up to 1.2 GPa in a piston-cylinder cell yields a linear increase of T-c with a positive coefficient dT(c)/dP = 1 K/GPa. Resistivity measurements up to 8 GPa in a cubic anvil apparatus show that Tc increases to 9.3 K at 8 GPa, but the slope decreases gradually with increasing pressure. Besides the previously reported LaFe4P12, YFe4P12 becomes the second filled skutterudite superconductor that exhibits a positive pressure coefficient dT(c)/dP in a broad pressure range. The observed large dT(c)/dP > 0 of YFe4P12 can be rationalized by our band-structure calculations that show an enhancement of density of states at Fermi energy and the Hopfield parameter under pressure at least up to 8 GPa. On the other hand, similar calculations predict a dT(c)/dP < 0 for YRu4P12.
Scientific journal, English - Magnetic properties of spinel CuCrZrS4 under pressure
Masakazu Ito; Naotoshi Kado; Kazuyuki Matsubayashi; Yoshiya Uwatoko; Norio Terada; Shuji Ebisu; Shoichi Nagata
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS, ELSEVIER SCIENCE BV, 331, 98-101, Apr. 2013, Peer-reviwed, We studied the magnetic properties of thiospinel CuCrZrS4 under pressure. At ambient pressure, the temperature dependence of magnetization shows a large irreversibility due to spin-glass freezing between the magnetizations with zero-field cooling and field cooling, with a sudden drop in the former below freezing temperature. The freezing temperature decreases with increasing magnetic field, and its dependence follows the de Almeida-Thouless line. The magnitude of the ac-magnetic susceptibility decreases with increasing pressure. Meanwhile, the freezing temperature increases monotonically with increasing pressure up to similar to 8 GPa. This means that the pressurization enhances the magnetic frustration coming from the characteristic crystal structure of CuCrZrS4. (C) 2012 Elsevier B.V All rights reserved.
Scientific journal, English - Dielectric properties of single crystal spinels in the series FeV 2O4, MnV2O4, and CoV 2O4 in high magnetic fields
A. Kismarahardja; J. S. Brooks; H. D. Zhou; E. S. Choi; K. Matsubayashi; Y. Uwatoko
Physical Review B - Condensed Matter and Materials Physics, 87, 5, 151-153, 27 Feb. 2013, Peer-reviwed, We report a comparative investigation of the magnetostrictive and magnetoconductivity effects in the low-temperature ferrimagnetic phases of the spinel vanadate structure AV2O4 (A = Fe, Mn, and Co). In FeV2O4, both the Fe and V sites have orbital degrees of freedom, the V-V distance places the compound intermediate between localized and itinerant charge carrier behavior, and there are three structural and two magnetic transitions versus temperature. For MnV2O4 and CoV2O4, only the V sites have orbital degrees of freedom. MnV2O4 has the largest V-V distance and the most localized conductivity, with one structural and one magnetic transition. CoV 2O4 has the shortest V-V distance and approaches the itinerant charge carrier threshold. CoV2O4 has one ferrimagnetic transition and no long-range ordered structural transition. Working with single crystals, ac dielectric and resistance measurements versus temperature and magnetic field exhibit distinctive physical properties in each case. These include the magnetocaloric signatures of magnetization reversal (Fe and Co), separable isotropic and anisotropic magnetostrictive effects (Mn), glasslike dynamics (Co), and evidence in the field-dependent dielectric response for the alteration of the ferrimagnetic spin structure with increasing magnetic field (Fe). These findings can guide future dielectric- and magnetoconductance-based spinel studies with a focus on the low-temperature and high magnetic field properties of canted ferrimagnetic spin configurations and orbital-lattice ordering effects. © 2013 American Physical Society.
Scientific journal, English - Pressure dependence of the superconducting transition temperature of the filled skutterudite YFe 4 P 12
Cheng, J-G.; Zhou, J-S.; Matsubayashi, K.; Kong, PP; Kubo, Y.; Kawamura, Y.; Sekine, Chihiro; Jin, CQ; Goodenough, JB; Uwatoko, Y.
Physical Review B, American Physical Society, 88, 2, 024514-024514, 2013
Scientific journal - Dielectric properties of single crystal spinels in the series FeV 2 O 4, MnV 2 O 4, and CoV 2 O 4 in high magnetic fields
Kismarahardja, A.; Brooks, JS; Zhou, HD; Choi, ES; Matsubayashi, K.; Uwatoko, Y.
Physical Review B, American Physical Society, 87, 5, 054432-054432, 2013
Scientific journal - Magnetic Field Effect on Magnetic and Electrical Properties of $${$$\backslash$hbox ${$Mn$}$$}$ _ ${$2$\backslash$hbox ${$-$}$${$$\backslash$rm x$}$$}$${$$\backslash$hbox ${$Cu$}$$}$ _ ${$$\backslash$rm x$}$${$$\backslash$hbox ${$Sb$}$$}$ $
Matsumoto, Yoshihiro; Orihashi, Hiroki; Matsubayashi, Kazuyuki; Uwatoko, Yoshiya; Hiroi, Masahiko; Koyama, Keiichi
IEEE transactions on magnetics, IEEE, 50, 1, 1-4, 2013
Scientific journal - Low energy excitations inside the vortex core of LiFe(As, P) single crystals investigated by microwave-surface impedance
T. Okada; H. Takahashi; Y. Imai; K. Kitagawa; K. Matsubayashi; Y. Uwatoko; A. Maeda
PHYSICA C-SUPERCONDUCTIVITY AND ITS APPLICATIONS, ELSEVIER SCIENCE BV, 484, 27-30, Jan. 2013, Peer-reviwed, The flux-flow resistivity and the electronic state inside the vortex core in single crystals of LiFe(As, P) were investigated by microwave-surface impedance. The flux-flow resistivity of these materials increase linearly with the magnetic field, and it is consistent with an isotropic gap nature of materials. However, the gradient is larger than theoretical predictions for superconductors with isotropic gap structure. It is probably the consequence of multiple-bands nature of these materials. We also found that the materials have the moderately clean core, and the mean free path of the quasi-particle inside the vortex core is much shorter than that outside the core, and rather comparable to the core radius. We believe that this is a novel and a universal feature of all superconductors. (C) 2012 Elsevier B. V. All rights reserved.
Scientific journal, English - Pressure and substitution effects on transport and magnetic properties of Y1-xRxCo2 systems with static magnetic disorder
Masataka Takeda; Atsushi Teruya; Shintaro Watanabe; Sentaro Hirakawa; Yuichi Hiranaka; Ai Nakamura; Yoshinao Takaesu; Kiyoharu Uchima; Masato Hedo; Takao Nakama; Katsuma Yagasaki; Kazuyuki Matsubayashi; Yoshiya Uwatoko; Alexander T. Burkov
Journal of the Physical Society of Japan, 82, 1, 4329-4331, Jan. 2013, Peer-reviwed, The electrical resistivity and thermopower of light- and heavy-rare-earth-based pseudo-binary Y1-xRxCo2 (R = Nd, Gd, and Tb) alloys are measured at temperatures from 2 to 300K under pressures up to 3.5 GPa. The resistivity and thermopower of Y 1-xRxCo2 show unusual large variations with atomic substitution and pressure in the range of x <
xm, where an inhomogeneous magnetization of the Co 3d electron subsystem is observed. These results indicate that the low-temperature transport properties of Y 1-xNdxCo2, as well as of Y1-xR H xCo2 (RH = heavy rare earth) alloys, are related to conduction electron scattering due to the static magnetic disorder in the itinerant Co 3d electron subsystem. We found that there is a universal relationship between d ln TC/dP and x/xm in Y1-xRxCo2 alloys, where xm is the boundary composition, which separates the alloy phase diagram into regions with uniform and nonuniform magnetizations of the Co-3d electron subsystem. © 2013 The Physical Society of Japan.
Scientific journal, English - Magnetic and structural properties of Mn
1.8 Co0.2 Sb under high magnetic fields
Hiroki Orihashi; Masahiko Hiroi; Yoshifuru Mitsui; Kohki Takahashi; Kazuo Watanabe; Kazuyuki Matsubayashi; Yoshiya Uwatoko; Keiichi Koyama
Materials Transactions, 54, 6, 969-973, 2013, Peer-reviwed, Magnetization, electrical resistivity and X-ray diffraction measurements were carried out for Mn1.8Co0.2Sb with a tetragonal structure in 4.2 ≤ T ≤ 280K and in field B up to 16 T. For B = 0 T, anisotropic structural deformation occurred at Tt ∼ 140K for zero-field cooling (ZFC), accompanied by a first-order magnetic transition from the ferrimagnetic (FRI) to antiferromagnetic (AFM) phases. In this deformation, the lattice parameters a and c changed by δ a/a=+0.15% and by δ c/c = -0.44%, respectively. By applying magnetic fields of 5 T, Tt decreased to 60K with thermal hysteresis of 35 K. The two-phase coexistence of the AFM and residual FRI phases was observed even at 10K for field cooling of 5 T, while a single phase of AFM was confirmed for ZFC. At B = 16 T, the transition did not occurs. In addition, a field-induced structural deformation was observed, accompanied by the metamagnetic transition just below Tt. The obtained results are discussed from a viewpoint on entropy change for the transition. © 2013 The Japan Institute of Metals and Materials.
International conference proceedings, English - Pressure-induced Suppression of the Antiferromagnetic Transition in YbNi3Al9 Single Crystal
T. Hirayama; K. Matsubayashi; T. Yamashita; S. Ohara; K. Munakata; Y. Uwatoko
Journal of Physics: Conference Series, 391, 1, 012020, 14 Dec. 2012, Peer-reviwed, We have measured the electrical resistivity ρ(T) of heavy fermion antiferromagnet YbNi3Al9 under hydrostatic pressure up to 8 GPa. We found that the antiferromagnetic ordering temperature TN is suppressed with increasing pressure, whereas the localized character of the trivalent Yb state becomes stronger inferred from the reduction of the Kondo scattering. We will discuss the possible origin of the suppression of TN under pressure. © Published under licence by IOP Publishing Ltd.
International conference proceedings, English - NMR studies of Yb-based heavy Fermion compound YbCo2Zn20
Takuma Ishida; Takeshi Mito; Keitaro Nakagawara; Takehide Koyama; Koichi Ueda; Takao Kohara; Kazuyuki Matsubayashi; Yuta Saiga; Koji Munakata; Yoshiya Uwatoko
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, PHYSICAL SOC JAPAN, 81, Dec. 2012, Peer-reviwed, We have carried out Co-59-nuclear magnetic resonance (NMR) measurements on the heavy Fermion compound YbCo2Zn20, which shows an extremely large specific heat. After examining site symmetry at the Co position by studying a single crystal sample at different directions of magnetic field, we have analyzed powder patterns obtained over a wide range of field from 0.8 to 7.2 T. The temperature dependent component of the Knight shift, which arises from 4f moments, is largely suppressed with increasing field, resulting in weak temperature dependence at low temperatures. This is a sign of field-induced Fermi liquid states, consistent with previous transport measurements on this compound.
Scientific journal, English - Effect of pressure on the neutron spin resonance in the unconventional superconductor FeTe0.6Se0.4
K. Marty; A. D. Christianson; A. M. dos Santos; B. Sipos; K. Matsubayashi; Y. Uwatoko; J. A. Fernandez-Baca; C. A. Tulk; T. A. Maier; B. C. Sales; M. D. Lumsden
PHYSICAL REVIEW B, AMER PHYSICAL SOC, 86, 22, 7069-7073, Dec. 2012, Peer-reviwed, We have carried out a pressure study of the unconventional superconductor FeTe0.6Se0.4 up to 1.5 GPa by neutron scattering, resistivity, and magnetic susceptibility measurements. The neutron spin resonance energy and the superconducting transition temperature have been extracted as a function of applied pressure in samples obtained from the same crystal. Both increase with pressure up to amaximum at approximate to 1.3 GPa, directly demonstrating a correlation between these two fundamental parameters of unconventional superconductivity. A comparison between the quantitative evolution of T-c and the resonance energy as a function of applied pressure is also discussed. These measurements serve to demonstrate the feasibility of using pressure dependent inelastic neutron scattering to explore the relationship between the resonance energy and T-c in unconventional superconductors. DOI: 10.1103/PhysRevB.86.220509
Scientific journal, English - Pressure-Induced Heavy Fermion Superconductivity in the Nonmagnetic Quadrupolar System PrTi2Al20
K. Matsubayashi; T. Tanaka; A. Sakai; S. Nakatsuji; Y. Kubo; Y. Uwatoko
PHYSICAL REVIEW LETTERS, AMER PHYSICAL SOC, 109, 18, Nov. 2012, Peer-reviwed, We report the discovery of a pressure-induced heavy fermion superconductivity in a nonmagnetic orbital ordering state in the cubic compound PrTi2Al20. In particular, we found that the transition temperature and the effective mass associated with the superconductivity are dramatically enhanced as the system approaches the putative quantum critical point of the orbital order. Our experiment indicates that the strong orbital fluctuations may provide a nonmagnetic glue for Cooper pairing.
Scientific journal, English - Investigation of the superconducting gap structure in SrFe2(As0.7P0.3)(2) by magnetic penetration depth and flux flow resistivity analysis
Hideyuki Takahashi; Tatsunori Okada; Yoshinori Imai; Kentaro Kitagawa; Kazuyuki Matsubayashi; Yoshiya Uwatoko; Atsutaka Maeda
PHYSICAL REVIEW B, AMER PHYSICAL SOC, 86, 14, 3028-3031, Oct. 2012, Peer-reviwed, We measured the microwave surface impedances and obtained the superfluid density and flux flow resistivity in single crystals of a phosphor-doped iron-based superconductor SrFe2(As1-xPx)(2) single crystals (x = 0.30, T-c = 25 K). At low temperatures, the superfluid density, n(s)(T)/n(s)(0), obeys a power law, n(s)(T)/n(s)(0) = 1 - C(T/T-c)(n), with a fractional exponent of n = 1.5-1.6. The flux flow resistivity was significantly enhanced at low magnetic fields. These features are consistent with the presence of line nodes on at least one band and modulated nodeless gap with deep minimum on the same bands and/or other bands. The remarkable difference observed in the superconducting gap structure between SrFe2(As1-xPx)(2) and BaFe2(As1-xPx)(2) in our experiments is important for clarifying the mechanism of iron-based superconductivity in the 122 system.
Scientific journal, English - High-pressure studies on T-c and crystal structure of iron chalcogenide superconductors
Hiroki Takahashi; Takahiro Tomita; Hiroyuki Takahashi; Yoshikazu Mizuguchi; Yoshihiko Takano; Satoshi Nakano; Kazuyuki Matsubayashi; Yoshiya Uwatoko
SCIENCE AND TECHNOLOGY OF ADVANCED MATERIALS, NATL INST MATERIALS SCIENCE, 13, 5, 969-973, Oct. 2012, Peer-reviwed, True, The superconducting transition temperature, T-c, in iron-based solids can be enhanced by applied pressure: T-c increases from 8 to 37 K for the 11-type FeSe when the pressure is raised from 0 to 4 GPa. High-pressure studies can elucidate the mechanism of superconductivity in such novel materials. In this paper, we present a high-pressure study of Fe(Se1-xTex) and Fe(Se1-xSx). In the case of Fe(Se1-xTex), the maximum T-c under high pressure did not exceed the T-c of FeSe, which can be attributed to the structural transition to the monoclinic phase. For Fe(Se1-xSx) (0 < x < 0.3), T-c exhibited a significant increase with pressure; however, the maximum T-c under high pressure did not exceed the T-c of FeSe. This may be due to the disorder induced by substituting S for Se, which is similar to the pressure effect on T-c for the 1111-type superconductor Ca(Fe1-xCox) AsF. The Tc of Fe(Se1-xSx) showed a complex behavior below 1 GPa, first decreasing and then increasing with increasing pressure. From high-pressure x-ray diffraction measurements, the T-c (P) curve was correlated with the local structural parameter.
Scientific journal, English - Microwave surface-impedance measurements of the electronic state and dissipation of magnetic vortices in superconducting LiFeAs single crystals
T. Okada; H. Takahashi; Y. Imai; K. Kitagawa; K. Matsubayashi; Y. Uwatoko; A. Maeda
PHYSICAL REVIEW B, AMER PHYSICAL SOC, 86, 6, Aug. 2012, Peer-reviwed, LiFeAs is one of the iron-based superconductors that has multiple gaps with a possible sign reversal. To clarify how those characteristics affect the energy dissipation of magnetic vortices, we investigated the microwave surface impedance of LiFeAs single crystals under finite magnetic fields. The flux-flow resistivity enhanced rapidly at low magnetic fields, which is similar to the case of MgB2. This is probably a consequence of the multiple-gap nature and the gap anisotropy. This suggest that the sign reversal is not important for the flux flow, even for multiple-gap superconductors. As for the electronic state, the vortex core of LiFeAs turned out to be "moderately clean." Furthermore, the mean free path inside the vortex core was much shorter than that outside, and was close to the core radius. These results strongly suggest that a process specific to the core boundary is important for a scattering mechanism inside the vortex core.
Scientific journal, English - Determination of spin Hamiltonian in the Ni-4 magnetic molecule
K. Iida; S. -H. Lee; T. Onimaru; K. Matsubayashi; T. J. Sato
PHYSICAL REVIEW B, AMER PHYSICAL SOC, 86, 6, 595-598, Aug. 2012, Peer-reviwed, Magnetic excitations in a Ni-4 magnetic molecule were investigated by inelastic neutron scattering and bulk susceptibility (chi(bulk)) techniques. The magnetic excitation spectrum obtained from the inelastic neutron scattering experiments exhibits three modes at energy transfers of (h) over bar omega = 0.5, 1.35, and 1.6 meV. We show that the energy, momentum, and temperature dependencies of the inelastic neutron scattering data and chi(bulk) can be well reproduced by an effective spin Hamiltonian consisting of intramolecule exchange interactions, a single-ionic anisotropy, biquadratic interactions, and a Zeeman term. Under hydrostatic pressure, the bulk magnetization decreases with increasing pressure, which along with the biquadratic term indicates spin-lattice coupling present in this system.
Scientific journal, English - Pressure Effect on the Structural Transition and Suppression of the High-Spin State in the Triple-Layer T-'-La4Ni3O8
J. -G. Cheng; J. -S. Zhou; J. B. Goodenough; H. D. Zhou; K. Matsubayashi; Y. Uwatoko; P. P. Kong; C. Q. Jin; W. G. Yang; G. Y. Shen
PHYSICAL REVIEW LETTERS, AMER PHYSICAL SOC, 108, 23, Jun. 2012, Peer-reviwed, We report a comprehensive high-pressure study on the triple-layer T-'-La4Ni3O8 with a suite of experimental probes, including structure determination, magnetic, and transport properties up to 50 GPa. Consistent with a recent ab inito calculation, application of hydrostatic pressure suppresses an insulator-metal spin-state transition at P-C approximate to 6 GPa. However, a low-spin metallic phase does not emerge after the high-spin state is suppressed to the lowest temperature. For P > 20 GPa, the ambient T-' structure transforms gradually to a T-dagger-type structure, which involves a structural reconstruction from fluorite La-O-2-La blocks under low pressures to rock-salt LaO-LaO blocks under high pressures. Absence of the metallic phase under pressure has been discussed in terms of local displacements of O(2-)ions in the fluorite block under pressure before a global T-dagger phase is established.
Scientific journal, English - Pressure-induced positive electrical resistivity coefficient in Ni-Nb-Zr-H glassy alloy
M. Fukuhara; C. Gangli; K. Matsubayashi; Y. Uwatoko
APPLIED PHYSICS LETTERS, AMER INST PHYSICS, 100, 25, 151-153, Jun. 2012, Peer-reviwed, Measurements under hydrostatic pressure of the electrical resistivity of (Ni0.36Nb0.24Zr0.40)(100-x)H-x (x = 9.8, 11.5, and 14) glassy alloys have been made in the range of 0-8 GPa and 0.5-300 K. The resistivity of the (Ni0.36Nb0.24Zr0.40)(86)H-14 alloy changed its sign from negative to positive under application of 2-8 GPa in the temperature range of 300-22 K, coming from electron-phonon interaction in the cluster structure under pressure, accompanied by deformation of the clusters. In temperature region below 22 K, the resistivity showed negative thermal coefficient resistance by Debye-Waller factor contribution, and superconductivity was observed at 1.5 K. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4729574]
Scientific journal, English - Growth and characterization of Bi2Se3 crystals by chemical vapor transport
W. H. Jiao; S. Jiang; C. M. Feng; Z. A. Xu; G. H. Cao; M. Xu; D. L. Feng; A. Yamada; K. Matsubayashi; Y. Uwatoko
AIP ADVANCES, AMER INST PHYSICS, 2, 2, 728-729, Jun. 2012, Peer-reviwed, Regularly-shaped high-quality Bi2Se3 crystals were grown by a chemical vapor transport using iodine as the transport agent. In addition to exhibiting a characteristic Dirac cone for a topological insulator, the Bi2Se3 crystals show some outstanding properties including additional crystallographic surfaces, large residual resistance ratio (similar to 10), and high mobility (similar to 8000 cm(2) . V-1 . s(-1)). The low-temperature resistivity abnormally increases with applying pressures up to 1.7 GPa, and no superconductivity was observed down to 0.4 K. Copyright 2012 Author(s). This article is distributed under a Creative Commons Attribution 3.0 Unported License. [http://dx.doi.org/10.1063/1.4727957]
Scientific journal, English - Pressure effects on the superconducting transition of ytterbium doped Ce0.6Yb0.4FeAsO0.9F0.1
S. Arumugam; M. Kanagaraj; N. R. Tamil Selvan; S. Esakki Muthu; J. Prakash; G. S. Thakur; A. K. Ganguli; H. Yoshino; K. Murata; K. Matsubayashi; Y. Uwatoko
PHYSICA STATUS SOLIDI-RAPID RESEARCH LETTERS, WILEY-V C H VERLAG GMBH, 6, 5, 220-222, May 2012, Peer-reviwed, The Effect of pressure on the superconducting transition temperature of Yb doped Ce0.6Yb0.4FeAsO0.9F0.1 has been investigated for the first time using resistivity and magnetization studies. Increase in chemical pressure by substitution of smaller Yb3+ ions in place of Ce3+ ions results in a significant enhancement of Tc from 38 K (Yb free) to 47 K (40% Yb). Enhancement in Tc with external pressure has been observed for this compound up to a maximum value of Tc = 48.7 K at 1 GPa, beyond which Tc starts decreasing monotonously. (C) 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
Scientific journal, English - Conductivity and incommensurate antiferromagnetism of Fe
1.02 Se0.10 Te0.90 under pressure
N. Katayama; K. Matsubayashi; Y. Nomura; S. Ji; J. Leao; M. A. Green; T. J. Sato; Y. Uwatoko; M. Fujita; K. Yamada; R. Arita; S. H. Lee
EPL, 98, 3, 747-750, May 2012, Peer-reviwed, By performing resistivity, bulk susceptibility and neutron diffraction on single crystals of Fe 1.02Se 0.10Te 0.90 under pressure, we show that an external pressure can enhance both conductivity and magnetism simultaneously. Surprisingly, the pressure-induced magnetic order is nearly three-dimensional, and incommensurate along both the c-axis and the a-axis, which is accompanied by a structural phase separation. Our powder neutron diffraction data show that the Fe(Se, Te) 4 tetrahedron becomes more regular under pressure, which is consistent with the enhancement of the metallicity but is counterintuitive to the three-dimensional magnetic order. © 2012 Europhysics Letters Association.
Scientific journal, English - Weakly ferromagnetic metallic state in heavily doped Ba 1-xK xMn 2As 2
Jin-Ke Bao; Hao Jiang; Yun-Lei Sun; Wen-He Jiao; Chen-Yi Shen; Han-Jie Guo; Ye Chen; Chun-Mu Feng; Hui-Qiu Yuan; Zhu-An Xu; Guang-Han Cao; Ryo Sasaki; Toshiki Tanaka; Kazuyuki Matsubayashi; Yoshiya Uwatoko
Physical Review B - Condensed Matter and Materials Physics, 85, 14, 25 Apr. 2012, Peer-reviwed, Heavily doped Ba 1-xK xMn 2As 2 (x=0.19 and 0.26) single crystals were successfully grown and investigated by the measurements of resistivity and anisotropic magnetization. In contrast to the antiferromagnetic insulating ground state of the undoped BaMn 2As 2, the K-doped crystals show metallic conduction with weak ferromagnetism below ∼50 K and Curie-Weiss-like in-plane magnetic susceptibility above ∼50 K. Under high pressures up to 6 G Pa, the low-temperature metallicity changes into a state characterized by a Kondo-like resistivity minimum. Electronic structure calculations for x=0.25 using a 2×2×1 supercell reproduce the hole-doped metallic state. The density of states at Fermi energy has significant As-4p components, indicating that the 4p holes are mainly responsible for the metallic conduction. Our results suggest that the interplay between the itinerant 4p holes and the local 3d moments is mostly responsible for the novel metallic state. © 2012 American Physical Society.
Scientific journal, English - Weakly ferromagnetic metallic state in heavily doped Ba1-xKxMn2As2
Jin-Ke Bao; Hao Jiang; Yun-Lei Sun; Wen-He Jiao; Chen-Yi Shen; Han-Jie Guo; Ye Chen; Chun-Mu Feng; Hui-Qiu Yuan; Zhu-An Xu; Guang-Han Cao; Ryo Sasaki; Toshiki Tanaka; Kazuyuki Matsubayashi; Yoshiya Uwatoko
PHYSICAL REVIEW B, AMER PHYSICAL SOC, 85, 14, Apr. 2012, Peer-reviwed, Heavily doped Ba1-xKxMn2As2 (x = 0.19 and 0.26) single crystals were successfully grown and investigated by the measurements of resistivity and anisotropic magnetization. In contrast to the antiferromagnetic insulating ground state of the undoped BaMn2As2, the K-doped crystals show metallic conduction with weak ferromagnetism below similar to 50 K and Curie-Weiss-like in-plane magnetic susceptibility above similar to 50 K. Under high pressures up to 6 G Pa, the low-temperature metallicity changes into a state characterized by a Kondo-like resistivity minimum. Electronic structure calculations for x = 0.25 using a 2 x 2 x 1 supercell reproduce the hole-doped metallic state. The density of states at Fermi energy has significant As-4p components, indicating that the 4p holes are mainly responsible for the metallic conduction. Our results suggest that the interplay between the itinerant 4p holes and the local 3d moments is mostly responsible for the novel metallic state.
Scientific journal, English - Mechanism of Field Induced Fermi Liquid State in Yb-Based Heavy-Fermion Compound: X-ray Absorption Spectroscopy and Nuclear Magnetic Resonance Studies of YbCo2Zn20
Takeshi Mito; Takehide Koyama; Keitaro Nakagawara; Takuma Ishida; Koichi Ueda; Takao Kohara; Kazuyuki Matsubayashi; Yuta Saiga; Koji Munakata; Yoshiya Uwatoko; Masaichiro Mizumaki; Naomi Kawamura; Bogdan Idzikowski; Marian Reiffers
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, PHYSICAL SOC JAPAN, 81, 3, 747-750, Mar. 2012, Peer-reviwed, We have investigated the field dependences of Yb valence as well as of the magnetic properties of the heavy-fermion (HF) compound YbCo2Zn20 by X-ray absorption spectroscopy, Co-59 nuclear magnetic resonance, and magnetization measurements. Our results clearly show that the mechanism of field-induced Fermi-liquid-like behavior does not involve variation in the Yb electronic configuration, and is of magnetic origin. Typical examples of the susceptibility for several Yb-based HF materials are presented, in which one can see systematic changes between localized and delocalized pictures of 4f electrons.
Scientific journal, English - Anisotropy of Upper Critical Field in a One-Dimensional Organic System, (TMTTF)(2)PF6 under High Pressure
Mika Kano; Hatsumi Mori; Kazuyuki Matsubayashi; Miho Itoi; Masato Hedo; Timothy P. Murphy; Stanley W. Tozer; Yoshiya Uwatoko; Toshikazu Nakamura
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, PHYSICAL SOC JAPAN, 81, 2, 78-83, Feb. 2012, Peer-reviwed, We have measured the temperature-dependent resistivity of (TMTTF)(2)PF6 up to 7 GPa using a turnbuckle-type diamond anvil cell (DAC) and at magnetic fields of up to 5 T. Unlike previous reports on organic compounds, a zero resistance was observed in the superconducting state even at high pressures. Superconductivity was observed in the range of P = 4.18 to 6.03 GPa and showed a peak T-c of 2.25K at 4.58 GPa. The temperature dependence of the upper critical magnetic field H-c2(T) was determined via resistivity at P = 4.58 GPa, for the intrachain (a), interchain (b'), and interlayer (c*) configurations, and H-c2(T) displays a positive curvature without saturation. This could be related to the wide pressure range of the coexistence between the spin density wave (SDW) and superconductivity (SC) ground state, and may be caused by an FFLO state, for a magnetic field along the a- and b'-axes with T >= 0: 5K for P = 4.48 GPa. This feature is suppressed with increasing pressure when the orbital pair breaking mechanism becomes dominant. The Ginzburg-Landau coherence lengths for three different axes obtained from this work show that (TMTTF)(2)PF6 is an anisotropic three-dimensional superconductor.
Scientific journal, English - Pressure and Substitution Effects on Transport and Magnetic Properties of Y1-x R x Co2 Systems with Static Magnetic Disorder
Takeda, Masataka; Teruya, Atsushi; Watanabe, Shintaro; Hirakawa, Sentaro; Hiranaka, Yuichi; Nakamura, Ai; Takaesu, Yoshinao; Uchima, Kiyoharu; Hedo, Masato; Nakama; Takao a
Journal of the Physical Society of Japan, The Physical Society of Japan, 82, 1, 014708-014708, 2012
Scientific journal - Conductivity and incommensurate antiferromagnetism of Fe1. 02Se0. 10Te0. 90 under pressure
Katayama, N.; Matsubayashi, K.; Nomura, Y.; Ji, S.; Leao, J.; Green, MA; Sato, TJ; Uwatoko, Y.; Fujita, M.; Yamada, K.
EPL (Europhysics Letters), IOP Publishing, 98, 3, 37002-37002, 2012
Scientific journal - Low temperature properties of a low carrier heavy fermion YbPtSb
K. Matsubayashi; R. Yamanaka; H. S. Suzuki; K. Munakata; Y. Uwatoko
INTERNATIONAL CONFERENCE ON STRONGLY CORRELATED ELECTRON SYSTEMS (SCES 2011), IOP PUBLISHING LTD, 391, 1, 2012, We have grown single crystals of a low carrier heavy fermion YbPtSb and studied low temperature properties by means of the electrical resistivity (rho), dc and ac magnetic susceptibility (chi), and specific heat (C). The clear evidence of the antiferromagnetic order at T-N similar to 0.34 K was observed by bulk measurements. At lower temperatures below T-N, extrapolating C/T to T=0 yields gamma similar to 9 J/mole K-2, and rho(T) shows T-2 temperature dependence with a large A coefficient, as observed in YbPtBi. We will discuss the Fermi liquid state realized in the low carrier systems.
International conference proceedings, English - Peculiar magnetic phase diagrams of GdPd
2 Si2 single crystal
Y. Zhang; T. Fujiwara; K. Matsubayashi; A. Kondo; K. Kindo; Y. Uwatoko; T. Shigeoka
Journal of Physics: Conference Series, 391, 1, 2012, High field magnetization measurement were performed up to 45 T using a long pulse magnet on a GdPd2Si2 single crystal compound having the tetragonal ThCr2Si2-type crystal structure and an antiferromagnetic ordering of TN=16.7 K. The magnetization processes are almost typical antiferromagnetic ones with a weak magnetic anisotropy though small anomalies exist in the processes. The magnetization saturates 7 μB/f.u. above Bs=32 T. The B001-T and B100-T magnetic phase diagrams were constructed. There are three phases, the phase I, II and III, under non-magnetic field in the ordered state for both diagrams. The field-induced phase, phase IV, appears below the paramagnetic phase by the [100] magnetic field, B100, which is accompany with a re-entrant behaviour. The B100 makes the phase II be stable and the phase I and III be instable. These strange behaviours indicate the direction of the magnetic moment changes in each phase. © Published under licence by IOP Publishing Ltd.
International conference proceedings - Magnetization processes and phase diagram of HoRh
2 Si2 single crystal having a component-separated magnetic transition
T. Shigeoka; T. Fujiwara; K. Matsubayashi; Y. Uwatoko
Journal of Physics: Conference Series, 391, 1, 2012, Thermal variations of magnetization under various magnetic fields and magnetization processes at various temperatures have been studied on a HoRh2Si2 single crystal compound. Three anomalies at TN1=29.1 K, Tt=27.3 K and TN2=12.0 K exist at low field in the thermal variation. The thermal dependence of M/B and the magnetization change drastically with magnetic field. Step-like metamagnetic processes appear along the all directions below TN2; two-step ones appear along the [001] and [100] directions, and a one-step one appears along the [110] direction. For TN2 - Recent Progress in Multi-Extreme Condition by Miniature High-Pressure Cell
Kazuyuki Matsubayashi; Akihiko Hisada; Tatsuya Kawae; Yoshiya Uwatoko
Review of High Pressure Science and Technology/Koatsuryoku No Kagaku To Gijutsu, 22, 3, 206-213, 2012, Peer-reviwed, In this article, we report recent development of miniature high-pressure apparatus for bulk measurements at low temperature and in magnetic field. The new compact multi-anvil type “Palm cubic anvil cell” extends the temperature range down to ~0.45 K by using a 3He refrigerator. We also present a technique for measuring the specific heat under pressure and magnetic field using newly developed miniature piston cylinder cell made of Ag-Pd-Cu alloy. Its application to the heavy fermion compound YbCo2Zn20 is presented. © 2012, The Japan Society of High Pressure Science and Technology. All rights reserved.
Scientific journal, English - Magnetic properties of Ce1-xLaxRu2Si 2 compounds
D. Abe; Y. Amakai; S. Murayama; N. Momono; H. Takano; T. Nakano; K. Matsubayashi; Y. Uwatoko
Journal of Physics: Conference Series, Institute of Physics Publishing, 391, 1, 12001, 2012, Peer-reviwed, We have measured the susceptibility χ and resistivity ρ on single-crystalline Ce1-xLaxRu2Si2 for 0 ≤ x ≤ 0.8 in directions parallel (//) and perpendicular (⊥) to the c-axis. The χ// for 0.1 ≤ x ≤ 0.7 indicates a Curie-Weiss form at T >
20 K and a typical AF maximum at TN. A significant crossover between TN and the magnitude of the Weiss temperature |Θ| occurs at about x = 0.2. The ρ⊥ shows a gap-type upturn at TN for 0.1 ≤ x ≤ 0.185 with rather a downward bend ρ// at around TN. The upturn in ρ⊥ at TN disappears for x = 0.2 with a sharp maximum ρ// at TN. A sharp peak in ρ⊥ takes place at TN for 0.3 ≤ x ≤ 0.7 with the sharp maximum ρ// at TN for 0.4 ≤ x ≤ 0.6. These results can be interpreted as the evolution from the itinerant SDW in the heavy-fermion band for 0.1 ≤ x <
0.2 to the AF ordering with the local moment for x >
0.2 up to x = 0.7. © Published under licence by IOP Publishing Ltd.
International conference proceedings, English - Pressure Effects on Electrical Resistivity of Heavy-Fermion Antiferromagnet Ce2PdGa12
S. Ohara; T. Yamashita; T. Shiraishi; K. Matsubayashi; Y. Uwatoko
26TH INTERNATIONAL CONFERENCE ON LOW TEMPERATURE PHYSICS (LT26), PTS 1-5, IOP PUBLISHING LTD, 400, 042048, 2012, Peer-reviwed, We have succeeded in growing high purity single crystalline Ce2PdGa12 which crystallizes in the tetragonal system (space group P4/nbm). Ce2PdGa12 is a typical heavy-fermion antiferromagnet with the magnetic ordering temperature of 11K at ambient pressure. We investigate the pressure effects on the electrical resistivity for Ce2PdGa12 up to 8GPa. With increasing pressure, the ordering temperature is dramatically suppressed to 3K at 3GPa. The electronic state of Ce2PdGa12 are tuned by pressure from the heavy-fermion antiferromagnetic state to the non-magnetic state through a critical pressure around P-c similar to 7GPa.
International conference proceedings, English - Hall effect of Ce(Ru1-xFex)(2)Al-10 single crystal
Yukihiro Kawamura; Daishi Hirai; Takashi Nishioka; Kazuyuki Matsubayashi; Yoshiya Uwatoko; Hideki Yoshizawa; Chihiro Sekine
INTERNATIONAL CONFERENCE ON STRONGLY CORRELATED ELECTRON SYSTEMS (SCES 2011), IOP PUBLISHING LTD, 391, 2012, Peer-reviwed, The Hall resistivity rho(H) has been measured between 2 K and 300 K for pseudoternary compounds Ce(Ru1-xFex)(2)Al-10 (x=0.375, 0.625, 1) single crystals up to 7 T. The rho(H) shows linear dependence against magnetic field except low temperatures. We calculated Hall coefficient R-H by the gradient of rho(H) under the field between 5 T and 7 T, where the anomalous Hall effect expected to be small. While R-H for CeRu2Al10 drastically increases below mysterious antiferromagnetic ordering temperature (T-0 similar to 27 K), R-H decreases by replacing Ru with Fe. The R-H becomes negative at lowest temperatures for x = 0.375, x = 0.625 and x = 1. The reversal of the sign suggests that Ce(Ru1-xFex)(2)Al-10 is in a multicarrier system.
International conference proceedings, English - Magnetic phase diagram and crystalline electric field of NdRu2Al10 single crystal
Kawamura Yukihiro; Tanimoto Sakiyo; Nishioka Takashi; Tanida Hiroshi; Sera Masafumi; Matsubayashi Kazuyuki; Uwatoko Yoshiya; Kondo Akihiro; Kindo Koichi; Sekine Chihiro
INTERNATIONAL CONFERENCE ON STRONGLY CORRELATED ELECTRON SYSTEMS (SCES 2011), IOP PUBLISHING LTD, 391, 2012, Peer-reviwed, We measured specific heat of NdRu2Al10 single crystal under magnetic field along a-axis in order to investigate basic physical properties of this compound. We found three anomalies at T-1 similar to 2.4 K, T-2 similar to 1.2 K and T-3 similar to 0.9 K in the temperature dependence of specific heat. These anomalies are attributed to antiferromagnetic order. In addition, we observed a Schottky-type anomaly, which reflects splitting of crystalline electric field (CEF). The entropy reaches Rln2 just above T-1 and almost reaches Rln10 at room temperature. These results indicate that these three phase transitions occur in a doublet ground state and that all CEF levels of J = 9/2 are below 300K. The results of specific heat are consistent with the CEF level scheme proposed by magnetization measurement.
International conference proceedings, English - Pressure effect of transport properties of hexagonal Yb2Ni12P7
Nakano Tomohito; Satoh Ryohei; Tsuchiya Katsuhiko; Takeda Naoya; Matsubayashi Kazuyuki; Uwatoko Yoshiya
INTERNATIONAL CONFERENCE ON STRONGLY CORRELATED ELECTRON SYSTEMS (SCES 2011), IOP PUBLISHING LTD, 391, 1, 12052, 2012, Peer-reviwed, We prepared single crystals of Yb2Ni12P7 using a Sn-flux method and measured their resistivity under hydrostatic pressure up to 8 GPa. At ambient pressure, the magnetic part of resistivity rho(mag)(T) shows a peak around T-max similar to 100 K and T-2 dependence below the characteristic temperature of the Fermi liquid, T-FL = 3 K. When pressure increases up to 2.06 GPa, the value of rho(mag)(T) above T-max decreases slightly but rho(mag) below T-max increases slightly. TFL decreases with increasing pressure, and is expected to become zero at 2.5 GPa. Around this pressure, the coefficient of T-2 in rho(mag) significantly increases, suggesting the existence of a quantum critical point. Above 2.5 GPa, overall rho(mag) gradually decreases with increasing pressure up to 6 GPa, but it below 15.5 K increases above 6 GPa.
International conference proceedings, English - 10 GPa-Class High-Pressure NMR Technique Realized by the New Cell with Improved Space Efficiency
Kentaro Kitagawa; Kazuyuki Matsubayashi; Hirotada Gotou; Takehiko Matsumoto; Yoshiya Uwatoko; Takehiko Yagi; Masashi Takigawa
Review of High Pressure Science and Technology/Koatsuryoku No Kagaku To Gijutsu, 22, 3, 198-205, 01 Jan. 2012, We describe our recent progress in high-pressure nuclear magnetic resonance (NMR) technique, which extends the range of practical NMR experiments to 10 GPa-class. The new opposed-anvil type cell has significantly large sample space, though the whole clamp cell size is small enough to put within superconducting magnets or fridges. We also show other new techniques on loading of argon pressure transmitting medium, pressure determination, and wiring of electrodes. The application on a pressure-induced superconductivity of SrFe2As2has demonstrated a remarkable advantage brought by the combination of the clean crystal, pressure control, and spectroscopy. © 2012, The Japan Society of High Pressure Science and Technology. All rights reserved.
Scientific journal, Japanese - Heat capacity measurement of heavy fermion YbCo
2 Zn20 under magnetic field
R. Yamanaka; K. Matsubayashi; Y. Saiga; T. Kawae; Y. Uwatoko
Journal of Physics: Conference Series, 391, 1, 2012, Peer-reviwed, We have measured the specific heat of heavy fermion YbCo2Zn20 down to 0.1 K under magnetic field up to 3 T. At zero-field, the electronic contribution to the specific heat Ce/T shows logarithmic increase with decreasing temperature and tends to saturate at lower temperature, reflecting the Fermi-liquid state. With increasing magnetic field, Ce/T exhibits a power-law divergence at Hm ∼ 0.6 T, which corresponds to the critical field of the metamagnetic crossover. The field dependence of Ce/T shows the two peak structure and the local minimum point of this structure coincides with Hm as observed in prototypical metamagnetic compound CeRu2Si2. We will compare the characteristic energy scale relevant to the metamagnetic behavior of YbCo2Zn20 and CeRu2Si2. © Published under licence by IOP Publishing Ltd.
International conference proceedings - Superconducting Transitions and Crystal Structure for FeSe1-xSx (x=0.2) under Pressure
Takahiro Tomita; Hiroki Takahashi; Hiroyuki Takahashi; Hironari Okada; Yoshikazu Mizuguchi; Yoshihiko Takano; Kazuyuki Matsubayashi; Yoshiya Uwatoko
JOURNAL OF PHYSICS：CONFERENCE SERIE, IOP PUBLISHING LTD, 400, 022125-1-022125-5, 2012, Peer-reviwed, '11'-type FeSe has the simplest structure in all categories of Fe-based superconductors and has a record of maximum T-c of 37 K under high pressure. These results show the T-c is very sensitive to pressure. In this paper, pressure effect for optimally S doped FeSe1-xSx (x=0.2) has been carried out using the electrical resistivity and X-ray diffraction measurements. As a result of these pressure experiments of FeSe1-xSx (x=0.2), the pressure-temperature phase diagram is determined by electrical resistivity up to 8 GPa. In the phase diagram, it is observed that after the T-c slightly decreases with application of pressure up to 0.6 GPa, the T-c jumps up above 0.6 GPa and reaches to T-c(x=0.2)=36.3 K at 6 GPa with large pressure derivative of T-c (= 10.7 K/GPa). The behavior of T-c(P) in the region of P <= 0.6 GPa are unconventional. Moreover, we observed that structural phase transition from tetragonal to hexagonal above 9 GPa using X-ray diffraction measurements at room temperature.
International conference proceedings, English - Upper Critical Field of the Stoichiometric Fe-based Superconductor LiFeAs
Kurita N; Kitagawa K; Matsubayashi K; Kismarahardja A; Choi E. S; Brooks J. S; Uwatoko Y; Uji S; Terashima T; Sebastian SE; Sutherland ML; Pugh E; Grosche FM; Keeling J; Panagopoulos C; Rowley S; Saxena SS
International Conference on Strongly Correlated Electron Systems (Sces 2011), 391, NA, NA, 2012, Peer-reviwed, We have investigated the upper critical field Bc2 of the stoichiometric Fe-based superconductor LiFeAs, via the magnetic torque measurements in dc-magnetic fields up to 35 T and at temperatures down to 0.3 K. Bc2 at 0.3K is obtained to be 26.4 T and 15.5 T for the applied field Ba || ab and Ba || c, respectively, indicating nearly-isotropic superconductivity. The detailed analyses show that, while Bc2 for Ba || c is limited by the orbital effect, the spin-paramagnetic effect is evident in the temperature dependence of Bc2 for Ba || ab. © Published under licence by IOP Publishing Ltd.
International conference proceedings - Magnetism and Pressure-induced Superconductivity of Checkerboard-type Charge-ordered Molecular Conductor -(meso-DMBEDT-TTF)2X (X = PF6 and AsF6)
Takahisa Shikama; Tatsuya Shimokawa; Sangchul Lee; Takayuki Isono; Akira Ueda; Kazuyuki Takahashi; Akiko Nakao; Reiji Kumai; Hironori Nakao; Kensuke Kobayashi; Youichi Murakami; Motoi Kimata; Hiroyuki Tajima; Kazuyuki Matsubayashi; Yoshiya Uwatoko; Yutaka Nishio; Koji Kajita; Hatsumi Mori
Crystals, MDPI AG, 2, 4, 1502-1513, 2012, Peer-reviwed, The metallic state of the molecular conductor beta-(meso-DMBEDT-TTF)(2)X (DMBEDT-TTF = 2-(5,6-dihydro-1,3-dithiolo[4,5-b][1,4] dithiin-2-ylidene)-5,6-dihydro5,6-dimethyl-1,3-dithiolo[4,5-b][1,4]dithiin, X = PF6, AsF6) is transformed into the checkerboard-type charge-ordered state at around 75-80 K with accompanying metal-insulator (MI) transition on the anisotropic triangular lattice. With lowering temperatures, the magnetic susceptibility decreases gradually and reveals a sudden drop at the MI transition. By applying pressure, the charge-ordered state is suppressed and superconductivity appears in beta-(meso-DMBEDT-TTF)(2)AsF6 as well as in the reported beta-(meso-DMBEDT-TTF)(2)PF6. The charge-ordered spin-gapped state and the pressure-induced superconducting state are discussed through the paired-electron crystal (PEC) model, where the spin-bonded electron pairs stay and become mobile in the crystal, namely the valence-bond solid (VBS) and the resonant valence bonded (RVB) state in the quarter-filled band structure.
Scientific journal, English - Correlation between superconductivity and structural properties under high pressure of iron pnictide superconductor Ce0.6Y0.4FeAsO0.8F0.2
M. Kanagaraj; S. Arumugam; Ravhi S. Kumar; N. R. Tamil Selvan; S. Esakki Muthu; J. Prakash; Gohil S. Thakur; H. Yoshino; K. Murata; K. Matsubayashi; Y. Uwatoko; S. Sinogeikin; Andrew Cornelius; A. K. Ganguli; Yusheng Zhao
APPLIED PHYSICS LETTERS, AMER INST PHYSICS, 100, 5, 728-729, Jan. 2012, Peer-reviwed, We report here the pressure dependence of the electrical resistivity and magnetic susceptibility of polycrystalline Ce0.6Y0.4FeAsO0.8F0.2 superconductor in the temperature range 4K to 300K up to 8 GPa. In-situ high pressure-low temperature x-ray diffraction was performed at 8K up to 32 GPa using synchrotron x-rays with helium pressure medium. The results show that the applied pressure slightly increases the T-c up to 1 GPa and then it decreases on further pressure increase. The reduction of superconducting transition temperature occurs with a transition to a collapsed tetragonal phase and may be associated with a possible valence change of Ce. (C) 2012 American Institute of Physics. [doi:10.1063/1.3681805]
Scientific journal, English - Scanning tunneling microscopy/spectroscopy of vortices in LiFeAs
Hanaguri, T.; Kitagawa, K.; Matsubayashi, K.; Mazaki, Y.; Uwatoko, Y.; Takagi, H.
Physical Review B, 85, 21, 595-598, 2012, Peer-reviwed
Scientific journal, English - Discontinuous Transition from a Real Bound State to Virtual Bound State in a Mixed-Valence State of SmS
Keiichiro Imura; Shinkichi Kanematsu; Kazuyuki Matsubayashi; Hiroyuki S. Suzuki; Kazuhiko Deguchi; Noriaki K. Sato
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, PHYSICAL SOC JAPAN, 80, 11, 78-83, Nov. 2011, Peer-reviwed, Golden SmS is a paramagnetic, mixed-valence system with a pseudogap. With increasing pressure across a critical pressure P-c, the system undergoes a discontinuous transition into a metallic, anti-ferromagnetically ordered state. By using a combination of thermodynamic, transport, and magnetic measurements, we show that the pseudogap results from the formation of a local bound state with spin singlet. We further argue that the transition P-c is regarded as a transition from an insulating electron-hole gas to a Kondo metal, i.e., from a spatially bound state to a Kondo virtually bound state between 4f and conduction electrons.
Scientific journal, English - Microwave surface impedance measurements of LiFeAs, LiFe(As,P) and FeSe1-xTex single crystals
Y. Imai; H. Takahashi; T. Okada; T. Yoshinaka; S. Komiya; K. Kitagawa; K. Matsubayashi; I. Tsukada; Y. Uwatoko; A. Maeda
PHYSICA C-SUPERCONDUCTIVITY AND ITS APPLICATIONS, ELSEVIER SCIENCE BV, 471, 21-22, 630-633, Nov. 2011, Peer-reviwed, We study microwave surface impedance measurements of LiFeAs, LiFe(As,P) and FeSe1-xTex single crystals. The in-plane penetration depths of LiFeAs and LiFe(As,P) depend on temperature exponentially at low temperatures, which is a strong indication that these two materials have the nodeless superconducting gap. The temperature dependence of the superfluid density indicates that LiFeAs and LiFe(As,P) are multi-gap superconductors with at least two isotropic gaps. In FeSe1-xTex on the other hand, the quadratic temperature dependence of the in-plane penetration depth appears, which indicates the existence of some sort of quasiparticle excitations. In addtion, the real part of the microwave conductivity exhibits a large enhancement below T-c in all three materials, which results from the increase of the quasiparticle relaxation time, tau, below T-c. 2011 Elsevier B.V. All rights reserved.
Scientific journal, English - Effects of Magnetic Field, Pressure and Dilution of Yb on Phase Transitions in Valence Fluctuating Compound YbPd
Masaki Sugishima; Kenji Yamada; Akihiro Mitsuda; Hirofumi Wada; Kazuyuki Matsubayashi; Yoshiya Uwatoko; Ken-ichi Suga; Koichi Kindo
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, PHYSICAL SOC JAPAN, 80, Jul. 2011, Peer-reviwed, High field magnetization, pressure effect on electrical resistivity and dilution of Yb with Lu were examined for YbPd. The high field magnetization suggests that half of Yb ions have magnetic moments between 50 K and 115 K up to 55 T. The phase transition temperatures, T-1 and T-2, which are observed under ambient pressure at 125 K and 105 K, respectively, decrease with increasing pressure and the transitions disappear at around 4 GPa. This indicates that the valence fluctuating state above T-1 and T-2 becomes stable down to zero temperature above 4 GPa. Substitution of Lu for Yb also leads to depression of T-1 and T-2, which is possibly caused by disturbing the periodicity of Yb ions. These results suggest that the valence ordered state of Yb ions is realized in YbPd below T-1 or T-2.
Scientific journal, English - Magnetic Phase Diagram of Ce1-xGdxRu2Al10 Single Crystals
Riki Kobayashi; Yukihiro Kawamura; Takashi Nishioka; Harukazu Kato; Masahiro Matsumura; Kazuto Kodama; Hiroshi Tanida; Masafumi Sera; Kazuyuki Matsubayashi; Yoshiya Uwatoko
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, PHYSICAL SOC JAPAN, 80, S594-S595, Jul. 2011, Peer-reviwed, CeRu2Al10 shows an unknown phase transition at T-0 similar to 27 K, and GdRu2Al10 shows a simple RKKY-type antiferromagnetic one at T-N similar to 16.5 K. In order to clarify the origin of the transition of CeRu2Al10, we have investigated the relationship between these phase transitions from the electrical resistivity, magnetization and specific heat measurements using pseudoternary Ce1-xGdxRu2Al10 single crystals grown by the Al self-flux method. When x increases to 0.3, T-0 decreases slightly and then disappears abruptly at x=0.4. On the other hand, T-N decreases monotonically with x, and coexists with T-0 at x=0.1 and 0.3. These results indicate that the unknown phase transition of CeRu2Al10 is independent of the antiferromagnetic one of GdRu2Al10, which suggests that the unknown phase transition cannot be described by only RKKY-type interaction.
Scientific journal, English - Hall coefficient for CeRu2Al10 under pressure
Y. Kawamura; Y. Ogane; T. Nishioka; H. Kato; M. Matsumura; D. Tanaka; H. Tanida; M. Sera; A. Kondo; K. Matsubayashi; Y. Uwatoko
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, PHYSICAL SOC JAPAN, 80, 151-153, Jul. 2011, Peer-reviwed, The Hall effect on single crystal of CeRu2Al10 under pressure has been studied to investigate semiconducting behavior which appears in electrical resistivity below 15 K. In addition, the Hall effect on single crystal of isostructual CeFe2Al10 at ambient pressure has been studied. The Hall coefficient R-H(T) of CeFe2Al10 increases with decreasing temperature from room temperature, whereas it decreases below 90 K. The sign of R-H(T) is changed from positive to negative at 45 K. R-H(T) of CeRu2Al10 at ambient pressure is positive at all temperatures and increases with decreasing temperature. It shows a kink at To and increases largely after the kink The pressure effect on R-H(T) of CeRu2Al10 was measured from 0 GPa to 2.1 GPa. The magnitude of R-H(T) below 15 K is gradually suppressed by applying pressure. We assumed CeT2Al10 to be compensate metal, because this compound has four molecules. The results of R-H(T) of CeFe2Al10 indicate that the dominant mobility of carrier is changed from holes to electrons at 45 K. Pressure effect of R-H(T) on CeRu2Al10 indicate that the concentrations of carriers or the sum of the mobility decreases but the difference between the mobility of carriers also decreases with increasing pressure.
Scientific journal, English - Thermoelectric Power Investigation on SmS
Keiichiro Imura; Shinkichi Kanematsu; Kazuhiko Deguchi; Hiroyuki S. Suzuki; Kazuyuki Matsubayashi; Noriaki K. Sato
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, PHYSICAL SOC JAPAN, 80, Jul. 2011, Peer-reviwed, We construct a measurement system of the absolute thermoelectric power, and present experimental results of the Seebeck coefficient S (T, P) of samarium mono-sulphide (SmS) at ambient and high pressure. At ambient pressure, S (T) of SmS exhibits negative sign and its absolute value vertical bar S vertical bar steeply increases with lowering temperature, indicating that the dominant charge carrier is an electron and the energy gap opens at Fermi level. When increasing pressure at room temperature, S (P) sharply changes from a negative to positive value at the black-to-golden phase transition, indicating that the dominant carrier changes from electrons to holes possibly associated with the discontinuous collapse of the band gap at the transition.
Scientific journal, English - Construction of a Magnetometer Using a Piezo Actuator
Kazuhiko Deguchi; Tsuyoshi Furukawa; Seiko Ban; Keiichiro Imura; Kazuyuki Matsubayashi; Noriaki K. Sato
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, PHYSICAL SOC JAPAN, 80, 78-83, Jul. 2011, Peer-reviwed, We have developed a compact magnetometer of the magnetization measurement using a commercial piezo actuator, which works at low temperatures and high magnetic fields. This magnetometer can also be used with multiple refrigerator inserts interchangeably for its compactness. We describe specifications and performances of the magnetometer in a He-4 cryostat, and present results of the magnetization measurements for paramagnetic salts to assure the accuracy and the resolution of this magnetometer in the static magnetization measurements.
Scientific journal, English - Pressure-induced changes in the magnetic and valence state of EuFe2As2
K. Matsubayashi; K. Munakata; M. Isobe; N. Katayama; K. Ohgushi; Y. Ueda; N. Kawamura; M. Mizumaki; N. Ishimatsu; M. Hedo; I. Umehara; Y. Uwatoko
PHYSICAL REVIEW B, AMER PHYSICAL SOC, 84, 2, 725-728, Jul. 2011, Peer-reviwed, We present the results of electrical resistivity, ac specific heat, magnetic susceptibility, x-ray absorption spectroscopy (XAS), and x-ray magnetic circular dichroism (XMCD) of the ternary iron arsenide EuFe2As2 single crystal under pressure. Applying pressure leads to a continuous suppression of the antiferromagnetism associated with Fe moments and the antiferromagnetic transition temperature becomes zero in the vicinity of a critical pressure P-c similar to 2.5-2.7 GPa. Pressure-induced reentrant superconductivity, which is highly sensitive to the homogeneity of the pressure, only appears in the narrow pressure region in the vicinity of P-c due to the competition between superconductivity and the antiferromagnetic ordering of Eu2+ moments. The antiferromagnetic state of Eu2+ moments changes to the ferromagnetic state above 6 GPa. We also found that the ferromagnetic order is suppressed with further increasing pressure, which is connected with a valence change of Eu ions.
Scientific journal, English - Electrical Resistivity of Ce2Ir3Ge5 under High Pressure
M. Nakashima; T. Kawata; Y. Amako; S. Yoshiuchi; Y. Hirose; K. Matsubayashi; Y. Uwatoko; A. Thamizhavel; F. Honda; R. Settai; Y. Onuki
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, PHYSICAL SOC JAPAN, 80, 895-897, Jul. 2011, Peer-reviwed, We measured electrical resistivity on antiferromagnet Ce2Ir3Ge5 under high pressure up to 8 GPa. It is shown that the Neel temperature (= 9.5 K) at ambient pressure decreased by increased pressure. The Neel temperature seems to be zero at a critical pressure P-c similar or equal to 2.0 GPa suddenly. The variation by higher pressure above 2.0 GPa does not seem prominence up to 8 GPa.
Scientific journal, English - Two different anisotropic SDW gaps in heavy-fermion system Ce0.87La0.13(Ru1-xRhx)(2)Si-2 by resistivity
Y. Amakai; E. Harada; D. Yokoyama; S. Murayama; K. Matsumoto; H. Takano; N. Momono; K. Matsubayashi; Y. Uwatoko
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, PHYSICAL SOC JAPAN, 80, 728-729, Jul. 2011, Peer-reviwed, We have measured the susceptibility chi and resistivity rho on single-crystalline Ce0.87La0.13(Ru1-xRhx)(2)Si-2 for 0 <= x <= 0.4 in directions parallel (parallel to) and perpendicular (perpendicular to) to the c-axis. The chi parallel to for 0 <= x <= 0.3 indicates a typical AF maximum at T-N. The rho perpendicular to for x = 0 and 0.05 shows a gap-type anomaly at T-N. The rho parallel to indicates a weak inflection at around T-N for x = 0 and a clear shoulder at T-N for x = 0.05. For 0.1 <= x <= 0.3 the gap-type anomaly in rho perpendicular to disappears and a gap-type jump has been detected in rho parallel to at T-N. These behaviors suggest that the Fermi-surface nesting along the a-axis for x = 0 followed by a transverse SDW ordering changes into the nesting along the c-axis followed by a longitudinal SDW ordering for 0.1 <= x <= 0.3.
Scientific journal, English - Crossover from Commensurate to Incommensurate Antiferromagnetism in Stoichiometric NaFeAs Revealed by Single-Crystal Na-23,As-75-NMR Experiments
Kentaro Kitagawa; Yuji Mezaki; Kazuyuki Matsubayashi; Yoshiya Uwatoko; Masashi Takigawa
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, PHYSICAL SOC JAPAN, 80, 3, Mar. 2011, Peer-reviwed, We report the results of Na-23 and As-75 nuclear magnetic resonance (NMR) experiments on a self-flux grown high-quality single crystal of stoichiometric NaFeAs. The NMR spectra reveal a tetragonal to twinned-orthorhombic structural phase transition at T-O = 57K and an antiferromagnetic (AF) transition at T-AF = 45 K. The divergent behavior of nuclear relaxation rate near T-AF shows significant anisotropy, indicating that the critical slowing down of stripe-type AF fluctuations are strongly anisotropic in spin space. The NMR spectra at sufficiently low temperatures consist of sharp peaks showing a commensurate stripe AF order with a small moment of similar to 0.3 mu(B). However, the spectra just below T-AF exhibit a highly asymmetric broadening pointing to an incommensurate modulation. The commensurate-incommensurate crossover in NaFeAs shows a certain similarity to the behavior of SrFe2As2 under high pressure.
Scientific journal, English - Co[V-2]O-4: A Spinel Approaching the Itinerant Electron Limit
A. Kismarahardja; J. S. Brooks; A. Kiswandhi; K. Matsubayashi; R. Yamanaka; Y. Uwatoko; J. Whalen; T. Siegrist; H. D. Zhou
PHYSICAL REVIEW LETTERS, AMER PHYSICAL SOC, 106, 5, 2097-2102, Feb. 2011, Peer-reviwed, Studies of the structure, magnetization, and resistivity under pressure on stoichiometric normal spinel Co[V-2]O-4 single crystals show (i) absence of a structural distortion, (ii) abnormal magnetic critical exponents, and (iii) metallic conductivity induced by pressures at low temperatures. All these results prove that Co[V-2]O-4 sits on the edge of the itinerant-electron limit. Compared with similar measurements on Fe[V-2]O-4 and other A[V-2]O-4 studies, it is shown that a critical V-V separation for a localized-itinerant electronic phase transition exists.
Scientific journal, English - Pressure-induced changes in the magnetic and valence state of EuFe 2 As 2
Matsubayashi, K.; Munakata, K.; Isobe, M.; Katayama, N.; Ohgushi, K.; Ueda, Y.; Kawamura, N.; Mizumaki, M.; Ishimatsu, N.; Hedo, M.
Physical Review B, American Physical Society, 84, 2, 024502-024502, 2011
Scientific journal - Electrical transport properties of ternary phosphides RRu
2 P2 (R=La, Ce,Pr and Eu) with ThCr2 Si2 type crystal structure
T. Fujiwara; K. Kanto; K. Matsubayashi; Y. Uwatoko; T. Shigeoka
Journal of Physics: Conference Series, 273, 1, 2011, It was found the growth method of single crystals of ternary lanthanide transition metal phosphide RRu2P2 (R=La, Ce,Pr and Eu) with enough large volume to measure the macroscopic physical properties, such as magnetization, electrical resistivity and specific heat. As a result, we succeeded in the measurements of electrical resistivity with a sufficiently good accuracy and reveal an experimental evidence of the superconducting transition in LaRu2P2 for the first time. On the basis of the results of electrical resistivity measurements we discuss that how P-P bonding state does affect on the electrical transport properties of RRu2P 2 compounds. © Published under licence by IOP Publishing Ltd.
International conference proceedings - Magnetic and transport properties of CeT2Al10 (T = Fe, Ru, Os) under pressure
Yukihiro Kawamura; Yuta Ogane; Takashi Nishioka; Harukazu Kato; Masahiro Matsumura; Kazuyuki Matsubayashi; Yoshiya Uwatoko
INTERNATIONAL CONFERENCE ON STRONGLY CORRELATED ELECTRON SYSTEMS (SCES 2010), IOP PUBLISHING LTD, 273, 012038-1-012038-4, 2011, Peer-reviwed, The results of electrical resistivity rho measurements for CeT2Al10 (T = Fe, Ru, Os) under pressure are reported. The abrupt increase was observed at T-0 similar to 27 K for CeRu2Al10 and 29 K for CeOs2Al10 at ambient pressure. By applying pressure, To for CeRu2Al10 and CeOs2Al10 suddenly disappeared at 4 GPa and 2 GPa, respectively. Although the ground state of CeRu2Al10 is metal at ambient pressure, rho at low temperatures increased and the ground state became semiconductor at 2 GPa. The increase in rho suppressed above 3 GPa and the ground state became metal above 5 GPa. Magnetic contribution to CeRu2Al10 above 4 GPa shows maximum, which seems to be attributed to Kondo coherence. These systematical change in rho(T) was also observed in CeFe2Al10 and CeOs2Al10. From the pressure dependence of the temperature of the maximum, we suggests that CeFe2Al10 and CeOs2Al10 is corresponding to 3.2 GPa and 1.3 GPa of CeRu2Al10.
International conference proceedings, English - Magnetic properties of Ce(Ru1-xFex)(2)Al-10
Takashi Nishioka; Daishi Hirai; Yukihiro Kawamura; Harukazu Kato; Masahiro Matsumurta; H. Tanida; M. Sera; Kazuyuki Matsubayashi; Yoshiya Uwatoko
INTERNATIONAL CONFERENCE ON STRONGLY CORRELATED ELECTRON SYSTEMS (SCES 2010), IOP PUBLISHING LTD, 273, 2011, Peer-reviwed, YbFe2Al10-type CeRu2Al10 exhibits a mysterious phase transition at 27 K. The isostructural CeFe2Al10 is a Kondo semiconductor, whose macroscopic properties are very similar to those of CeRu2Al10 at a pressure of similar to 4 GPa. In order to clarify the relationship between the physical and chemical pressure effect on CeRu2Al10, we have performed measurements of the electrical resistivity, magnetic susceptibility and specific heat on pseudo-ternary Ce(Ru1-xFex)(2)Al-10 single crystals. These results suggest that Ce(Ru1-xFex)(2)Al-10 gives almost the same information as CeRu2Al10 under pressure, and furthermore the primary origin of the phase transition is not simple magnetic one.
International conference proceedings, English - Component-separated magnetic transition in HoRh2Si2 single crystal
T. Shigeoka; T. Fujiwara; K. Munakata; K. Matsubayashi; Y. Uwatoko
INTERNATIONAL CONFERENCE ON STRONGLY CORRELATED ELECTRON SYSTEMS (SCES 2010), IOP PUBLISHING LTD, 273, 2011, Peer-reviwed, Magnetic susceptibility and specific heat measurements have been carried out on a HoRh2Si2 single crystal compound. Specific heat shows two lambda-like anomalies at T-N1=29.1 K and T-N2=12.0 K, and an additional sharp anomaly indicating the first order transition at Tt=27.3 K. The temperature dependence of susceptibility along the [001] direction shows a clear cusp at T-N1 but a tiny kink at T-N2 and Tt. In contrast, those in the ab-plane show a clear cusp at T-N2. HoRh2Si2 shows a successive component-separated magnetic transition coming from a new type frustration not geometrical one.
International conference proceedings, English - Superconducting Phase at 7.7 K in the HgxReO3 Compound with a Hexagonal Bronze Structure
Kenya Ohgushi; Ayako Yamamoto; Yoko Kiuchi; Chandreyee Ganguli; Kazuyuki Matsubayashi; Yoshiya Uwatoko; Hidenori Takagi
PHYSICAL REVIEW LETTERS, AMER PHYSICAL SOC, 106, 1, 017001-017001, Jan. 2011, Peer-reviwed, True, We have successfully synthesized a new rhenium-based hexagonal bronze material, HgxReO3, which exhibits superconductivity with the transition temperature T-c = 7.7 K at ambient pressure and 11.1 K at 4 GPa. This compound is a superconductor with the highest T-c among hexagonal bronzes. Moreover, it presents the novel crystallographic feature that (Hg-2)(2+) polycations, in contrast to monatomic cations in known hexagonal bronzes, are incorporated into open channels. There is evidence that conducting electrons tightly couple with Hg-related phonons. Our results inspire detailed studies on the role of the rattling phonon in the occurrence of superconductivity in the hexagonal bronzes.
Scientific journal, English - Determination of the Upper Critical Field of a Single Crystal LiFeAs: The Magnetic Torque Study up to 35 Tesla
Nobuyuki Kurita; Kentaro Kitagawa; Kazuyuki Matsubayashi; Ade Kismarahardja; Eun-Sang Choi; James S. Brooks; Yoshiya Uwatoko; Shinya Uji; Taichi Terashima
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, PHYSICAL SOC JAPAN, 80, 1, 2097-2102, Jan. 2011, Peer-reviwed, We report on the upper critical field B-c2 of a superconducting LiFeAs single crystal with T-c similar to 16 K, determined from magnetic torque measurements in dc-magnetic fields up to 35 T and at temperatures down to 0.3 K. B-c2 at 0.3 K is obtained to be 26.4 and 15.5 T for the applied field B-a parallel to ab and B-a parallel to c, respectively. The anisotropy parameter Gamma = B-c2(ab)/B-c2(c) is similar to 3 at T-c and decreases to 1.7 as T -> 0, showing rather isotropic superconductivity. While B-c2 is orbitally-limited for Ba parallel to c, the spin-paramagnetic effect is evident in the temperature dependence of B-c2 for B-a parallel to ab.
Scientific journal, English - Microwave Surface Impedance Measurements of LiFeAs Single Crystals
Yoshinori Imai; Hideyuki Takahashi; Kentaro Kitagawa; Kazuyuki Matsubayashi; Noriyuki Nakai; Yuki Nagai; Yoshiya Uwatoko; Masahiko Machida; Atsutaka Maeda
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, PHYSICAL SOC JAPAN, 80, 1, 805-807, Jan. 2011, Peer-reviwed, We report results of microwave surface impedance measurements of LiFeAs single crystals. The in-plane penetration depth depends on temperature exponentially at low temperatures, which strongly suggests that this material has the nodeless superconducting gap. The temperature dependence of the superfluid density indicates that LiFeAs is a multigap superconductor with at least two isotropic gaps. In addtion, the real part of the microwave conductivity exhibits a large enhancement below T-c, indicating that the quasi-particle relaxation time, tau, increases rapidly below T-c. We believe that this enhancement is rather common to all superconductors where an inelastic scattering is dominant above T-c, irrespective of the strength of the electron correlation.
Scientific journal, English - Completely hydrostatic pressure effect of anisotropic resistivity in the 1-D organic conductor (TMTTF)(2)SbF6
Miho Itoi; Yasuyuki Ishii; Shuho Takekoshi; Haruhisa Kitano; Kazuyuki Matsubayashi; Yoshiya Uwatoko; Toshikazu Nakamura
PHYSICA C-SUPERCONDUCTIVITY AND ITS APPLICATIONS, ELSEVIER SCIENCE BV, 470, S594-S595, Dec. 2010, Peer-reviwed, The anisotropic resistivity of (TMTTF)(2)SbF6 under hydrostatic pressure was investigated up to similar to 0.3 GPa using a helium gas pressure control system. The resistivity along the a axis shows a metallic behavior above a crossover temperature T-rho (similar to 220 K at ambient pressure) and an insulating behavior below T-rho. On the other hand, the temperature dependence of P-b' and p(c). was found to show a kink at a charge ordered temperature T-co. Interestingly, T rho was increased with applying pressure while T-co was decreased with applying pressure. We discuss this unusual feature in terms of the pressure-temperature phase diagram in the (TMTCF)(2)X system. (C) 2009 Elsevier B.V. All rights reserved.
Scientific journal, English - Magnetic Field Effect on Yb-Based Heavy Fermions near Magnetic-Nonmagnetic Transition
T. Mito; T. Koyama; K. Nakagawara; T. Ishida; K. Ueda; T. Kohara; K. Matsubayashi; Y. Saiga; K. Munakata; Y. Uwatoko; M. Mizumaki; N. Kawamura
ACTA PHYSICA POLONICA A, POLISH ACAD SCIENCES INST PHYSICS, 118, 5, 870-872, Nov. 2010, Peer-reviwed, Recently magnetic field effects on f electron systems in the vicinity of a magnetic nonmagnetic transition have attracted much interest In order to investigate the mechanism of field induced modifications in heavy fermion systems, especially in terms of valent degrees of freedom, we have carried out the X-ray absorption spectroscopy measurement on the newly discovered heavy fermion material YbCo2Zn20 which exhibits extremely large specific heat at low temperatures Our results show that the Yb valence of YbCo2Zn20 is very close to +3 over the whole temperature range of measurement Besides, no significant change in the absorption spectrum was observed up to the field of 10 T This contrasts to the previously reported strong field dependence in the resistivity, followed by an expansion of the Fermi liquid regime with increasing field The obtained results therefore lead to the conclusion that the valent degrees of freedom play a minor role in the strong field dependence of the heavy fermion systems in this compound
Scientific journal, English - Magnetic ordering and dense Kondo behavior in EuFe2P2
Chunmu Feng; Zhi Ren; Shenggao Xu; Shuai Jiang; Zhu'an Xu; Guanghan Cao; I. Nowik; I. Felner; Kazuyuki Matsubayashi; Yoshiya Uwatoko
PHYSICAL REVIEW B, AMER PHYSICAL SOC, 82, 9, 799-801, Sep. 2010, Peer-reviwed, Ternary iron phosphide EuFe2P2 with ThCr2Si2-type structure has been systematically studied by the measurements of crystal structure, magnetization, Mossbauer effect, transport properties, and specific heat. The structural refinement result confirms no direct P-P covalent bonding. The Mossbauer spectra indicate no magnetic moment for the Fe atoms and that the Eu ions are divalent in the whole temperatures. The Eu2+ spins order ferromagnetically at T-C = 29 K, followed by a possible helimagnetic ordering below T-HM = 26 K, where the Eu2+ moments tilt a little from the c axis. External magnetic field increases the TC gradually but suppresses the THM rapidly. (Magneto)resistivity data indicate characteristic dense Kondo behavior above the Curie temperature. The result is discussed in terms of the interplay between intersite Ruderman-Kittel-Kasuya-Yosida and intrasite Kondo interactions.
Scientific journal, English - Effects of magnetic field and pressure on the intermediate valence state of YbPd
M. Sugishima; K. Yamada; A. Mitsuda; H. Wada; K. Matsubayashi; Y. Uwatoko; K. Suga; K. Kindo
JOURNAL OF PHYSICS-CONDENSED MATTER, IOP PUBLISHING LTD, 22, 37, 895-897, Sep. 2010, Peer-reviwed, High field magnetization, magnetoresistance and pressure effects of magnetic susceptibility, thermal expansion and electrical resistivity were examined for the intermediate valence system YbPd, which undergoes two first-order transitions at T(1) = 125 K and T(2) = 105 K. Analyses of high field magnetization suggest that half of the Yb atoms have magnetic moments below 100 K up to 55 T. The Yb valence state and the first-order transitions are stable up to 55 T. On the other hand, T(1) and T(2) decrease with increasing pressure and the first-order transitions disappear at around 4 GPa. Above the critical pressure, the experimental results suggest that the intermediate valence state persists down to the lowest temperature or a heavy fermion state is formed. We will show that most experimental results are explained reasonably by assuming the first-order transitions as a valence order transition of Yb. The magnetic ordering temperature is decreased with increasing pressure, in contrast to other Yb intermediate valence or Kondo systems. This may be correlated with the instability of the valence ordered state in this compound.
Scientific journal, English - Magnetic properties of Mn-rich Pd2MnSn Heusler alloys
T. Kanomata; K. Endo; Y. Chieda; T. Sugawara; K. Obara; T. Shishido; K. Matsubayashi; Y. Uwatoko; H. Nishihara; R. Y. Umetsu; M. Nagasako; R. Kainuma
JOURNAL OF ALLOYS AND COMPOUNDS, ELSEVIER SCIENCE SA, 505, 1, 29-33, Aug. 2010, Peer-reviwed, Pd2Mn1+xSn1-x(0 <= x <= 0.30) alloys crystallize in the cubic L2(1) structure. The lattice parameter a decreases linearly with increasing Mn concentration x. X-ray powder diffraction patterns indicate that the excess Mn atoms occupy the vacant Sn sites. All alloys exhibit the ferromagnetic behavior. The pressure change of the magnetic moment per formula unit at 5 K for Pd2MnSn is independent of pressure. The Curie temperature of Pd2Mn1+xSn1-x(0 <= x <= 0.30) alloys increases linearly with increasing x. Magnetization measurements make clear that the magnetic moment of Mn atoms, which substitute for Sn sites, is coupled antiferromagnetically to the magnetic moment of Mn atoms on the ferromagnetic Mn sublattice. (C) 2010 Elsevier B.V. All rights reserved.
Scientific journal, English - Effect of Pressure on Transport Properties of Heavy Fermion CePtSi2
Tomohito Nakano; Masashi Ohashi; Gendo Oomi; Kazuyuki Matsubayashi; Yoshiya Uwatoko
JOURNAL OF SUPERCONDUCTIVITY AND NOVEL MAGNETISM, SPRINGER, 23, 5, 799-801, Jul. 2010, Peer-reviwed, We measured the resistivity of heavy fermion CePtSi2 under pressure. At ambient pressure, CePtSi2 shows an antiferromagnetic (AF) transition at 2 K and a Fermi liquid like T-2 dependence ill resistivity below 1.5 K. With increasing pressure, the AF phase and T-2 dependence are suppressed. Above 1.4 GPa, a T linear dependence and pressure-induced superconductivity were found with the maximum T-c = 0.14 K at 1.7 GPa. Above 2 GPa, the T-2 dependence recovers just above T-c.
Scientific journal, English - Effect of hydrostatic pressure on magnetic phase transition and magnetocaloric properties of (Sm0.8Nd0.2)(0.52)Sr0.48MnO3
S. Arumugam; P. Sarkar; P. Mandal; A. Murugeswari; K. Matsubayashi; C. Ganguli; Y. Uwatoko
JOURNAL OF APPLIED PHYSICS, AMER INST PHYSICS, 107, 11, 8884-8886, Jun. 2010, Peer-reviwed, We have investigated the effect of hydrostatic pressure (P) on ferromagnetic (FM) phase transition and magnetocaloric properties of (Sm0.8Nd0.2)(0.52)Sr0.48MnO3 single crystal. At ambient pressure, the system undergoes a first order FM transition associated with large magnetic entropy change (Delta S-M). The temperature distribution of Delta S-M exhibits an asymmetric behavior with respect to T-C. The application of pressure increases magnetization, shifts the FM transition to higher temperature, and weakens the metamagnetism. As a result, vertical bar Delta S-M vertical bar decreases and its thermal distribution becomes more symmetric as compared to P=0. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3431343]
Scientific journal, English - Response of Itinerant-Electron Weak Ferromagnet LaFe4As12 to Pressure and Magnetic Field
Sho Tatsuoka; Makoto Watanabe; Bunya Suemitsu; Yoshinori Ogawa; Atsushi Yamada; Kazuyuki Matsubayashi; Yoshiya Uwatoko; Ryuji Higashinaka; Yuji Aoki; Takahiro Namiki; Keitaro Kuwahara; Hideyuki Sato
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, PHYSICAL SOC JAPAN, 79, 6, 725-728, Jun. 2010, Peer-reviwed, To investigate the quantum criticality and spin fluctuations in LaFe4As12, we have investigated the pressure and magnetic field dependences of electrical resistivity (rho). The Curie temperature T-C (similar to 5.2K at ambient pressure) is gradually suppressed by pressure (P) and disappears at approximately 2 GPa (similar to P-c). The coefficient A of the T-2 dependence of rho increases near P-c, and the exponent n of rho(T) similar to rho(0) + beta T-n changes into 5/3, which is expected for 3d ferromagnetic spin fluctuations. The low-field longitudinal magnetoresistance Delta rho/rho(T) is negative at low temperatures, as was commonly observed in typical itinerant-electron weak ferromagnets, reflecting a field-suppressed spin-fluctuation scattering. Above T-C, it becomes positive and shows a peak against magnetic field, which is hardly ascribable only to the ordinary positive magnetoresistance due to the Lorentz force on conduction electrons. Possible origins of the unexpected positive magnetoresistance are discussed by considering Kohler's plot for both the longitudinal and transverse magnetoresistances.
Scientific journal, English - La2Co2Se2O3: A Quasi-Two-Dimensional Mott Insulator with Unusual Cobalt Spin State and Possible Orbital Ordering
Cao Wang; Ming-qiu Tan; Chun-mu Feng; Zhi-feng Ma; Shuai Jiang; Zhu-an Xu; Guang-han Cao; Kazuyuki Matsubayashi; Yoshiya Uwatoko
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, AMER CHEMICAL SOC, 132, 20, 7069-7073, May 2010, Peer-reviwed, True, The new oxyselenide La2Co2Se2O3, containing Co2O square-planar layers, has been successfully synthesized using solid-state reactions under vacuum. The compound crystallizes in space group 14/mmm with lattice parameters a=4.0697(8) angstrom and c=18.419(4) angstrom. Magnetic susceptibility measurements indicate an antiferromagnetic transition at similar to 220 K. The magnetic entropy associated with the transition is close to R In 2, suggesting an unusual low-spin state for the Co2+ ions. The as-prepared sample shows insulating behavior with room-temperature resistivity of similar to 10(7) Omega cm, which decreases by 4 orders of magnitude under a pressure of 7 GPa. Band structure calculations using the LSDA+U approach reproduce the insulating ground state with low spin for Co and suggest strong orbital polarization for the valence electrons near the Fermi level. It is also revealed that the spin and orbital degrees of freedom in the antiferromagnetic checkerboard spin-lattice are mutually coupled.
Scientific journal, English - A cubic-anvil high-pressure device for pulsed neutron powder diffraction
J. Abe; M. Arakawa; T. Hattori; H. Arima; H. Kagi; K. Komatsu; A. Sano-Furukawa; Y. Uwatoko; K. Matsubayashi; S. Harjo; A. Moriai; T. Ito; K. Aizawa; M. Arai; W. Utsumi
REVIEW OF SCIENTIFIC INSTRUMENTS, AMER INST PHYSICS, 81, 4, 51-54, Apr. 2010, Peer-reviwed, A compact cubic-anvil high-pressure device was developed for in situ neutron powder diffraction studies. In this device, a cubic shaped pressure medium is compressed by six anvils, and neutron beams pass through gaps between the anvils. The first high-pressure experiment using this device was conducted at J-PARC and clearly showed the neutron diffraction patterns of Pb. Combining the cubic-anvil high-pressure device with a pulsed neutron source will prove to be a useful tool for neutron diffraction experiments.
Scientific journal, English - Pressure-induced ferromagnetic to antiferromagnetic phase transition in Ce2Ni5C3
Atsushi Yamada; Kazuyuki Matsubayashi; Yoshiya Uwatoko; Kenji Kondo; Susumu Katano; Masashi Kosaka
SOLID STATE COMMUNICATIONS, PERGAMON-ELSEVIER SCIENCE LTD, 150, 15-16, 725-728, Apr. 2010, Peer-reviwed, We have studied an effect of pressure on the ferromagnetism of Ce2Ni5C3 by ac susceptibility using a newly developed Palm cubic anvil cell up to 5.2 GPa. The ferromagnetic transition temperature of 2.3 K at ambient pressure is suppressed to zero at a critical pressure P similar to 3.8 GPa. Instead, another magnetic phase appears above this pressure. This new magnetic phase is considered to be antiferromagnetic from the result of the magnetic field dependence of the ac susceptibility. (C) 2010 Elsevier Ltd. All rights reserved.
Scientific journal, English - Pressure effect of superconducting oxypnictide LaFeAO1−xFx and related materials
H Takahashi; H Okada; Y Kamihara; S Matsuishi; M Hirano; H Hosono; K Matsubayashi; Y Uwatoko
Journal of Physics: Conference Series, 215, 012037, Mar. 2010, Peer-reviwed, Pressure dependence on superconducting transition temperature (T c) has been investigated for iron-based superconductor LaFeAsO 1-xFx, SmFeAsO1-xFx and Ca(Fe 1-xCox)AsF. The Tc increases largely for LaFeAsO1-xFx with a small increase of pressure, and decreases with further compression. In SmFeAsO1-xFx the Tc decreases with increasing pressure. The increase of Tc in LaFeAsO1-xFx seems to be related to the suppression of magnetic ordering phase. Pressure-induced superconductivity was observed for these materials. The common features on 1111 type superconductors are discussed. © 2010 IOP Publishing Ltd.
Scientific journal, English - Pressure dependence of the superconductor transition temperature of Ca(Fe1-xCox)AsF compounds: A comparison with the effect of pressure on LaFeAsO1-xFx
Hironari Okada; Hiroyuki Takahashi; Satoru Matsuishi; Masahiro Hirano; Hideo Hosono; Kazuyuki Matsubayashi; Yoshiya Uwatoko; Hiroki Takahashi
PHYSICAL REVIEW B, AMER PHYSICAL SOC, 81, 5, 2097-2102, Feb. 2010, Peer-reviwed, We performed systematic investigation of pressure effect on superconductivity in Ca(Fe1-xCox)AsF. Pressure-induced superconductivity was observed for x = 0.0 after suppression of the antiferromagnetically ordered orthorhombic phase at the critical pressure P-c similar to 5 GPa. Unlike the pressure effect on T-c in F-doped LaFeAsO, all the Co-doped superconductors show no marked enhancement, which is less than 1 K. Consequently, the highest T-c among Ca(Fe1-xCox)AsF was obtained in parent compound. These results suggest that Co doping suppresses superconductivity. The maximum T-c observed in parent compound is higher than that in LaFeAsO, suggesting that CaFeAsF is considered as a candidate parent compound for realizing higher T-c.
Scientific journal, English - Effect of pressure on the electrical resistivity of CeZn
3 P3
A. Yamada; N. Hara; K. Matsubayashi; K. Munakata; C. Ganguli; A. Ochiai; T. Matsumoto; Y. Uwatoko
Journal of Physics: Conference Series, 215, 2010, We have measured the electrical resistivity of CeZn3P 3 single crystals under pressure up to 19 GPa for temperature down to 0.4 K. At ambient pressure, the electrical resistivity shows a semiconducting behavior with an energy gap Eg ∼ 1800 K. We have found that the Eg monotonically decreases with increasing pressure, and possibly disappears at around 20 GPa. © 2010 IOP Publishing Ltd.
International conference proceedings - Pressure dependence of the superconductor transition temperature of Ca (Fe 1- x Co x) AsF compounds: A comparison with the effect of pressure on LaFeAsO 1- x F x
Okada, Hironari; Takahashi, Hiroyuki; Matsuishi, Satoru; Hirano, Masahiro; Hosono, Hideo; Matsubayashi, Kazuyuki; Uwatoko, Yoshiya; Takahashi, Hiroki
Physical Review B, American Physical Society, 81, 5, 054507-054507, 2010
Scientific journal - Magnetic ordering and dense Kondo behavior in EuFe 2 P 2
Feng, Chunmu; Ren, Zhi; Xu; Shenggao; Jiang, Shuai; Xu, Zhu’an; Cao, Guanghan; Nowik, I.; Felner, I.; Matsubayashi, Kazuyuki; Uwatoko, Yoshiya
Physical Review B, American Physical Society, 82, 9, 094426-094426, 2010
Scientific journal - High pressure electrical resistivity of CeCuAl3
Yukihiro Kawamura; Takashi Nishioka; Harukazu Kato; Masahiro Matsumura; Kazuyuki Matsubayashi; Yoshiya Uwatoko
INTERNATIONAL CONFERENCE ON MAGNETISM (ICM 2009), IOP PUBLISHING LTD, 200, 012082-1-4, 2010, Measurements of the electrical resistivity rho of an antiferromagnetic Kondo compound BaNiSn3-type CeCuAl3 at pressures up to 20 kbar using piston cylinder pressure cell and up to 80 kbar using a cubic anvil pressure cell are reported. The temperature dependence of rho at ambient pressure shows a kink for the Neel temperature at 3.4 K and the magnetic contribution in rho(T) indicates two broad peaks at 10 K and 150 K, respectively. The Neel temperature gradually increases with increasing pressure up to 60 kbar, and suddenly disappears at 80 kbar. The two broad peaks approach each other with pressure and merge into one broad peak at around 40 K at a pressure of 80 kbar. This pressure variation is well described by Kondo effect influenced by crystalline electric field effect, and indicates enhancement of Kondo effect with pressure. Since these results are qualitatively interpreted by Doniach's phase diagram, we suggest that CeCuAl3 is a weak Kondo antiferromagnet and quantum critical point exists between 60 and 80 kbar.
International conference proceedings, English - Pressure-Induced Variation of Kondo Behavior on the Heavy Fermion Compounds YbT2Zn20 (T = Co, Rh, Ir)
Kazuyuki Matsubayashi; Yuta Saiga; Takehiko Matsumoto; Yoshiya Uwatoko
INTERNATIONAL CONFERENCE ON MAGNETISM (ICM 2009), IOP PUBLISHING LTD, 200, SECTION 1, 2010, Peer-reviwed, We have performed the electrical resistivity measurement on single crystal heavy fermion compounds YbT2Zn20 (T = Co, Rh, Ir) under pressure up to 12 GPa. A pronounced resistivity maximum T-max, which scales with the Kondo temperature, develops with increasing pressure. In the case of YbCo2Zn20, T-max initially decreases with increasing pressure, reaches a minimum around 1 GPa, above which the pressure-induced magnetic ordering emerges at low temperature. For YbRh2Zn20 and YbIr2Zn20, T-max also exhibits a minimum at approximately 3 GPa, suggesting the appearance of pressure-induced magnetic transition below 2 K. Our results indicate the proximity to a magnetic instability in YbT2Zn20 systems at ambient pressure.
International conference proceedings, English - Novel Phase Transition and the Pressure Effect in YbFe2Al10-type CeT2Al10 (T = Fe, Ru, Os)
Takashi Nishioka; Yukihiro Kawamura; Tomoaki Takesaka; Riki Kobayashi; Harukazu Kato; Masahiro Matsumura; Kazuto Kodama; Kazuyuki Matsubayashi; Yoshiya Uwatoko
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, PHYSICAL SOC JAPAN, 78, 12, 743-746, Dec. 2009, Peer-reviwed, We have succeeded in growing single crystals of orthorhombic CeT2Al10 (T = Fe, Ru, and Os) by the Al self-flux method for the first time, and measured their electrical resistivity p at pressures of up to 8GPa, magnetic Susceptibility chi, and specific heat C at ambient pressure. The results indicate that CeT2Al10 belongs to the heavy fermion compounds. CeRu2Al10 and CeOs2Al10 show similar phase transitions at T-0 = 27.3 and 28.7 K, respectively. The temperature dependences of rho, chi, and C in the ordered phases are well described by the thermally activated form, Suggesting that a partial gap opens over the Fermi surfaces below T-0. When pressure is applied to CeRu2Al10, T-0 disappears suddenly between 3 and 4GPa, and CeRu2Al10 turns into a Kondo semiconductor, and then into a metal. The similarity of CeT2Al10 compounds under respective pressures suggests a scaling relation by some parameter controlling the unusual physics of these compounds.
Scientific journal, English - Orbital hybridization in RVO3 perovskites: A high-pressure study
J. -S. Zhou; J. B. Goodenough; J. -Q. Yan; J. -G. Cheng; K. Matsubayashi; Y. Uwatoko; Y. Ren
PHYSICAL REVIEW B, AMER PHYSICAL SOC, 80, 22, 969-973, Dec. 2009, Peer-reviwed, The RVO3 perovskites undergo orbital ordering and orbital-flipping transitions as well as a spin ordering transition. However, the existing model of orbital ordering fails to explain the thermal conductivity, which remains poor and glassy in the orbitally ordered phase. The phonon thermal conductivity is restored only below a first-order orbital-flipping transition. Orbital ordering induces a specific lattice distortion, which makes uniaxial pressure suitable to distinguish and verify all possible orbital and spin orderings in orthorhombic RVO3. We have made a systematic study of orbital/spin transitions in single-crystal samples of RVO3 (R=Dy, Y1-xLax) under uniaxial and hydrostatic pressure. Comparison of the uniaxial and hydrostatic pressure effects on the spin/orbital-flipping transition permits us to identify orbital fluctuations due to the hybridization of t(2) and et orbitals in the type-G orbitally ordered phase.
Scientific journal, English - Magnetic properties of Mn-rich Ni2MnSn Heusler alloys under pressure
Y. Chieda; T. Kanomata; K. Fukushima; K. Matsubayashi; Y. Uwatoko; R. Kainuma; K. Oikawa; K. Ishida; K. Obara; T. Shishido
JOURNAL OF ALLOYS AND COMPOUNDS, ELSEVIER SCIENCE SA, 486, 1-2, 51-54, Nov. 2009, Peer-reviwed, The pressure effect on the Curie temperature T-C of Heusler alloys Ni2Mn1+xSn1-x (0 <= x <= 0.28) has been investigated by measuring the temperature dependence of initial permeability at various pressures up to 10 kbar. The pressure derivative of T-C, dT(C)/dp, of Ni2MnSn is found to be +0.5 K/kbar. The values of dT(C)/dp for Ni2Mn1+xSn1-x (0 <= x <= 0.28) alloys decrease with increasing the concentration x. The pressure effect on T-C for Ni2Mn1+xSn1-x (0 <= x <= 0.28) alloys is discussed qualitatively on the basis of the interatomic dependence of the exchange interactions. (C) 2009 Elsevier B.V. All rights reserved.
Scientific journal, English - Possible Existence of Magnetic Polaron in Nearly Ferromagnetic Semiconductor beta-US2
Shugo Ikeda; Hironori Sakai; Naoyuki Tateiwa; Tatsuma D. Matsuda; Dai Aoki; Yoshiya Homma; Etsuji Yamamoto; Akio Nakamura; Yoshinobu Shiokawa; Yuuki Ota; Kiyohiro Sugiyama; Masayuki Hagiwara; Koichi Kindo; Kazuyuki Matsubayashi; Masato Hedo; Yoshiya Uwatoko; Yoshinori Haga; Yoshichika Onuki
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, PHYSICAL SOC JAPAN, 78, 11, 8884-8886, Nov. 2009, Peer-reviwed, We studied the magnetic properties of the paramagnet beta-US2 with an orthorhombic crystal structure by measuring its magnetization, magnetic susceptibility, specific heat, and electrical resistivity under magnetic field and pressure. The 5f-crystalline electric field (CEF) scheme was determined from the experimental results: a singlet in the ground state and a pseudo-doublet in the first excited state, separated by 85 and 91 K from the ground state. The insulating resistivity markedly changes to a metallic one under a high pressure of 8 GPa similarly to that of the semimetallic Ising-type ferromagnet UTeS with a Curie temperature T-C = 87 K. A resistivity anomaly was also observed in the temperature dependence of the resistivity under pressure, most likely corresponding to ferromagnetic ordering. From these experimental results, it was concluded that beta-US2 is in the vicinity of ferromagnetic ordering at ambient pressure. Furthermore, we found that the easy-axis magnetization at low fields for H parallel to [001] consists of a linear magnetization based on the 5f-CEF scheme and a ferromagnetic-like magnetization with a saturated moment of 0.042 mu(B)/U. The latter magnetization was analyzed on the basis of the ferromagnetic cluster and discussed from the viewpoint of the magnetic polaron.
Scientific journal, English - Thermodynamic and transport properties of SmS under high pressure
K. Imura; K. Matsubayashi; H. S. Suzuki; K. Deguchi; N. K. Sato
PHYSICA B-CONDENSED MATTER, ELSEVIER SCIENCE BV, 404, 19, 3028-3031, Oct. 2009, Peer-reviwed, We measured transport and thermodynamic properties of the valence-fluctuating phase of SmS up to 8.5 kbar, and found a bump structure in the temperature dependence of the electrical resistivity and a Schottky-type anomaly in the temperature dependence of the thermal expansion coefficient at a characteristic temperature T(0). We also observed that the absolute value of the Hall constant rapidly increases below T(0). From these results, we argue that the steep rise of the electrical resistivity below To is inherent to golden SmS and can be ascribed to the decrease in the carrier concentration possibly due to the pseudo gap formation. (C) 2009 Elsevier B.V. All rights reserved.
Scientific journal, English - Pressure-Temperature Phase Diagram of Golden SmS
Keiichiro Imura; Kazuyuki Matsubayashi; Hiroyuki S. Suzuki; Noriyuki Kabeya; Kazuhiko Deguchi; Noriaki K. Sato
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, PHYSICAL SOC JAPAN, 78, 10, 728-729, Oct. 2009, Peer-reviwed, We measured the thermal expansion of the valence fluctuating phase of SmS (golden SmS) to construct a pressure vs temperature phase diagram. The obtained phase diagram is characterized by three lines. One is a crossover line that divides the paramagnetic phase into two regions. The other two lines correspond to a second-order Neel transition and a first-order Neel transition. The crossover line appears to emerge from a tricritical point that separates the first-order Neel transition from the second-order one. We argue that a valence jump Occurs at the border of anti ferromagnetism.
Scientific journal, English - NMR and NQR study of pressure-induced superconductivity and the origin of critical-temperature enhancement in the spin-ladder cuprate Sr2 Ca12 Cu24 O41
N. Fujiwara; Y. Fujimaki; S. Uchida; K. Matsubayashi; T. Matsumoto; Y. Uwatoko
Physical Review B - Condensed Matter and Materials Physics, 80, 10, 98-101, 08 Sep. 2009, Peer-reviwed, Pressure-induced superconductivity was studied for a spin-ladder cuprate Sr2 Ca12 Cu24 O41 using nuclear magnetic resonance under pressures up to the optimal pressure 3.8 GPa. Pressure application leads to a transitional change from a spin-gapped state to a Fermi-liquid state at temperatures higher than Tc. The relaxation rate 1/ T1 shows activated-type behavior at an onset pressure, whereas Korringa-like behavior becomes predominant at the optimal pressure, suggesting that an increase in the density of states at the Fermi energy leads to enhancement of Tc. Nuclear quadrupole resonance spectra suggest that pressure application causes transfer of holes from the chain to the ladder sites. The transfer of holes increases DOS below the optimal pressure. A dome-shaped Tc versus pressure curve arises from naive balance between the transfer of holes and broadening of the band width. © 2009 The American Physical Society.
Scientific journal, English - NMR and NQR study of pressure-induced superconductivity and the origin of critical-temperature enhancement in the spin-ladder cuprate Sr2Ca12Cu24O41
N. Fujiwara; Y. Fujimaki; S. Uchida; K. Matsubayashi; T. Matsumoto; Y. Uwatoko
PHYSICAL REVIEW B, AMER PHYSICAL SOC, 80, 10, 100503-1-100503-4, Sep. 2009, Peer-reviwed, Pressure-induced superconductivity was studied for a spin-ladder cuprate Sr2Ca12Cu24O41 using nuclear magnetic resonance under pressures up to the optimal pressure 3.8 GPa. Pressure application leads to a transitional change from a spin-gapped state to a Fermi-liquid state at temperatures higher than T-c. The relaxation rate 1/T-1 shows activated-type behavior at an onset pressure, whereas Korringa-like behavior becomes predominant at the optimal pressure, suggesting that an increase in the density of states at the Fermi energy leads to enhancement of T-c. Nuclear quadrupole resonance spectra suggest that pressure application causes transfer of holes from the chain to the ladder sites. The transfer of holes increases DOS below the optimal pressure. A dome-shaped T-c versus pressure curve arises from naive balance between the transfer of holes and broadening of the band width.
Scientific journal, English - Chemical and Physical Pressure Effects on the Magnetic and Transport Properties of the A-Site Ordered Perovskite Sr3YCo4O10.5
Shin Yoshida; Wataru Kobayashi; Tomohito Nakano; Ichiro Terasaki; Kazuyuki Matsubayashi; Yoshiya Uwatoko; Inga Grigoraviciute; Maarit Karppinen; Hisao Yamauchi
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, PHYSICAL SOC JAPAN, 78, 9, 2097-2102, Sep. 2009, Peer-reviwed, We have measured and analysed the magnetization, resistivity and thermopower of polycrystalline samples of Ca-subsituted Sr3YCo4O10.5. While the transition temperature and thermopower systematically decrease with increasing Ca content, the resistivity is nearly independent of the Ca-substitution level. We have furhter found that the substitution of Ca for Sr systematically decreases the lattice paremeters while maintaining the oxygen content unchanged, and have explained the Ca-substitution effects in terms of the spin-state transition induced by chemical pressure. We have also measured the magnetization of one of the samples under hydrostatic pressure. The result shows that the physical-pressure effect is semiquantitatively consistent with the chemical-pressure effect.
Scientific journal, English - Transition from a weak ferromagnetic insulator to an exchange-enhanced paramagnetic metal in the BaIrO3 polytypes
J. -G. Cheng; J. -S. Zhou; J. A. Alonso; J. B. Goodenough; Y. Sui; K. Matsubayashi; Y. Uwatoko
PHYSICAL REVIEW B, AMER PHYSICAL SOC, 80, 10, E54-E56, Sep. 2009, Peer-reviwed, As a follow-up of the high-pressure synthesis and the structural determination of two new BaIrO3 polytypes, we report in this paper a systematic study of the physical properties of all polytypes available to us through measurements of magnetic, electronic transport, thermodynamic, and low-temperature structural as well as pressure effects. With increasing fraction of the corner-to face-sharing octahedra in the sequence 9R (hhChhChhC) -> 5H(hChCC) -> 6H(hCChCC), the ground states of BaIrO3 evolve from a ferromagnetic insulator with T-c approximate to 180 K in the 9R phase to a ferromagnetic metal with T-c approximate to 50 K in the 5H phase, and finally to an exchange-enhanced paramagnetic metal near a quantum critical point (QCP) in the 6H phase. The experimental results for the 9R phase confirm that the ferromagnetic transition is accompanied by a lattice instability, presumably associated with the formation of a charge density wave. The evidence includes a sudden increase in resistivity and thermoelectric power, an anomaly in the thermal conductivity, an unusual expansion of the c axis, and an extraordinarily large pressure coefficient of T-c. In contrast, the ferromagnetic transition in the 5H BaIrO3 only gives rise to weak anomalies in the resistivity and specific heat near T-c, similar to SrRuO3; the 5H phase is the first weak ferromagnetic metal among the known oxide iridates. The 6H phase remains a paramagnetic metal to the lowest temperature. However, a strongly enhanced thermoelectric power and a non-Fermi-liquid behavior from the resistivity measurement at low temperature show that quantum critical fluctuations play a role in this exchange-enhanced paramagnetic phase. A positive thermoelectric power confirms the charge carriers are holelike for all polytypes, which is consistent with the electronic configuration of Ir(IV) (5d(5)) in the low-spin state. The low-temperature specific-heat coefficients and Sommerfeld-Wilson ratios are in agreement with the evolution of the ground states across a ferromagnetic to paramagnetic QCP.
Scientific journal, English - High-Pressure Studies on Superconductivity in LaFeAsO1-x F (x) and SmFeAsO1-x F (x)
H. Takahashi; H. Okada; K. Igawa; Y. Kamihara; M. Hirano; H. Hosono; K. Matsubayashi; Y. Uwatoko
JOURNAL OF SUPERCONDUCTIVITY AND NOVEL MAGNETISM, SPRINGER, 22, 6, 595-598, Aug. 2009, Peer-reviwed, The pressure dependence on the superconducting transition temperature (T (c) ) was investigated for the iron-based superconductors LaFeAsO1-x F (x) and SmFeAsO1-x F (x) . The T (c) 's increase largely for LaFeAsO1-x F (x) with a small increase of pressure, while a sharp decrease of T (c) was observed for SmFeAsO1-x F (x) . The electrical resistivity measurements reveal pressure-induced superconductivity for undoped LaFeAsO and SmFeAsO. These pressure effects seem to be related to an anisotropic decrease of the lattice constants under high pressure from the x-ray diffraction measurements up to 10 GPa for the LaFeAsO1-x F (x) system.
Scientific journal, English - Intrinsic Properties of AFe(2)As(2) (A = Ba, Sr) Single Crystal under Highly Hydrostatic Pressure Conditions
Kazuyuki Matsubayashi; Naoyuki Katayama; Kenya Ohgushi; Atsushi Yamada; Koji Munakata; Takehiko Matsumoto; Yoshiya Uwatoko
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, PHYSICAL SOC JAPAN, 78, 7, 7069-7073, Jul. 2009, Peer-reviwed, We measured the electrical resistivity and ac magnetic susceptibility of BaFe2As2 and SrFe2As2 single crystals under pressure using a cubic anvil apparatus. For BaFe2As2, the antiferromagnetic (AF) and structural transitions are suppressed with increasing pressure. Unexpectedly, these transitions persist up to 8 GPa, and no signature of a superconducting transition was observed in the pressure range investigated here. On the other hand, the AF and structural transitions of SrFe2As2 collapse at around the critical pressure P-C similar to 5 GPa, resulting in the appearance of bulk superconductivity. The superconducting volume fraction abruptly increases above P-C, and shows a dome centered at approximately 6 GPa. Our results suggest that the bulk superconducting phase competes with the AF/orthorhombic phase and only appears in the narrow pressure region of the tetragonal phase.
Scientific journal, English - Pressure-induced superconductivity in the orthorhombic Kondo compound CePtSi2
Tomohito Nakano; Masashi Ohashi; Gendo Oomi; Kazuyuki Matsubayashi; Yoshiya Uwatoko
PHYSICAL REVIEW B, AMER PHYSICAL SOC, 79, 17, 870-872, May 2009, Peer-reviwed, We have discovered a member of superconductivity induced by hydrostatic pressure in an antiferromagnetic (AF) concentrated Kondo compound CePtSi2 by measuring the resistivity and magnetoresistance. The AF transition temperature T-N of 1.8 K at ambient pressure is suppressed by pressure and disappears around 1.2 GPa. Above 1.4 GPa, a superconducting phase appears between 1.4 and 2.4 GPa, with the maximum T-c of 0.14 K at 1.7 GPa. The upper critical field of the superconductivity is evaluated to be 0.7 T, which is clearly larger than that of the Pauli limit predicted by the BCS theory.
Scientific journal, English - Pressure Dependence of the Magnetic Properties of MnPS3
Wataru Toyoshima; Toshihiro Masubuchi; Tadataka Watanabe; Kouichi Takase; Kazuyuki Matsubayashi; Yoshiya Uwatoko; Yoshiki Takano
Journal of Physics: Conference Series, IOP PUBLISHING LTD, 150, 042215-1-4, 31 Mar. 2009, Peer-reviwed, The pressure dependence of the magnetic properties of two-dimensional transition metal phosphorus trichalcogenides MnPS3 has been investigated. In this compound, the lattice constant c which includes the van der Waals gap is reported to decrease rather rapidly with pressure, compared with the lattice constants a and b. The magnitude of the interlayer exchange interaction can be increased by reducing the van der Waals gap with applying a pressure. While the effective magnetic moment is almost independent of the pressure and close to spin only value of Mn2+ ion, the Neel temperature T-N and the spin flop magnetic field H-F show the pressure dependence. The increase rate of T-N and the decrease rate of H-F are 13 K/GPa and 4.0 x 10(3) Oe/GPa, respectively. These results are well explained by the increase of the dimensionality and the decrease of the anisotropy.
International conference proceedings, English - Pressure effects on Tc of Iron-based Layered Superconductor LaTMPO (TM = Fe, Ni)
K. Igawa; K. Arii; Y. Takahashi; H. Okada; H. Takahashi; Y. Kamihara; M. Hirano; H. Hiramatsu,T; Watanabe,H; Yanagi; T. Kamiya; H. Hosono; K. Matsubayashi; Y. Uwatoko
Journal of Physics: Conference Series, IOP Publishing, 150, 5, 52075-52078, 01 Mar. 2009, We report electrical and magnetic properties of LaTMPO (TM Fe, Ni) under high pressures. From resistivity measurements, superconducting transition temperature Tc for LaFePO and LaNiPO increases steeply up to about 0.8 GPa, and the dTc/dP values are more than 4 K/GPa and 1 K/GPa, respectively. From the results of high-pressure x-ray diffraction measurements, the oxypnictide compounds show an anisotropic compression along a-axis and c-axis. © 2009 IOP Publishing Ltd.
International conference proceedings, English - Pressure-Induced Superconductivity in Iron Pnictide Compound SrFe2As2
Kazumi Igawa; Hironari Okada; Hiroki Takahashi; Satoru Matsuishi; Yoichi Kamihara; Masahiro Hirano; Hideo Hosono; Kazuyuki Matsubayashi; Yoshiya Uwatoko
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, PHYSICAL SOC JAPAN, 78, 2, 2097-2102, Feb. 2009, Peer-reviwed
Scientific journal, English - Neutron powder diffraction under high pressure at J-PARC
Wataru Utsumi; Hiroyuki Kagi; Kazuki Komatsu; Hiroshi Arima; Takaya Nagai; Takuo Okuchi; Takashi Kamiyama; Yoshiya Uwatoko; Kazuyuki Matsubayashi; Takehiko Yagi
NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT, ELSEVIER SCIENCE BV, 600, 1, 50-52, Feb. 2009, Peer-reviwed, It is expected that high-pressure material science and the investigation of the Earth's interior will progress greatly using the high-flux pulse neutrons of J-PARC. In this article, we introduce our plans for in situ neutron powder diffraction experiments under high pressure at J-PARC. The use of three different types of high-pressure devices is planned; a Paris-Edinburgh cell, a new opposed-anvil cell with a nano-polycrystalline diamond, and a cubic anvil high-pressure apparatus. These devices will be brought to the neutron powder diffraction beamlines to conduct a "day-one" high-pressure experiment. For the next stage of research, we propose construction of a dedicated beamline for high-pressure material science. Its conceptual designs are also introduced here. (C) 2008 Elsevier B.V. All rights reserved.
Scientific journal, English - Development of pressure cell for specific heat measurement at low temperature and high Magnetic field
T. Kawae; K. Yaita; Y. Yoshida; Y. Inagaki; M. Ohashi; G. Oomi; K. Matsubayashi; T. Matsumoto; Y. Uwatoko
REVIEW OF SCIENTIFIC INSTRUMENTS, AMER INST PHYSICS, 80, 2, 78-83, Feb. 2009, Peer-reviwed, We report the performance of Ag-Pd-Cu alloy as the material of a pressure cell to carry out specific heat measurements at low temperatures and high magnetic fields. The Ag-Pd-Cu alloy is advantageous to reduce the background due to the nuclear specific heat in the pressure cell growing at low temperatures and high magnetic fields. We prepared 70-20-10 alloy composed of 70 mass % of Ag, 20 mass % of Pd, and 10 mass % of Cu. The maximum hardness over 100 HRB (Rockwell-B scale) is achieved by the heat treatment. The magnetization and susceptibility results show that the alloy includes a small amount of magnetic ions, whose concentration is smaller than that in the Be-Cu alloy. We confirm that the specific heat of a piston cylinder cell made of the 70-20-10 alloy increases smoothly from 0.2 to 9 K and the nuclear specific heat decreases drastically in magnetic field compared to that expected in the Be-Cu alloy. The pressure value in the cell at low temperature increases almost linearly up to P=0.4 GPa, which is nearly the limit of the inner piston made of the 70-20-10 alloy, with increasing of the load applied at room temperature.
Scientific journal, English - Pressure-induced superconductivity in the orthorhombic Kondo compound CePtSi 2
Nakano, Tomohito; Ohashi, Masashi; Oomi, Gendo; Matsubayashi, Kazuyuki; Uwatoko, Yoshiya
Physical Review B, American Physical Society, 79, 17, 172507-172507, 2009
Scientific journal - Intrinsic Properties of A Fe2As2 (A= Ba, Sr) Single Crystal under Highly Hydrostatic Pressure Conditions
Matsubayashi, Kazuyuki; Katayama, Naoyuki; Ohgushi, Kenya; Yamada, Atsushi; Munakata, Koji; Matsumoto, Takehiko; Uwatoko, Yoshiya
Journal of the Physical Society of Japan, The Physical Society of Japan, 78, 7, 073706-073706, 2009
Scientific journal - Fermi-liquid properties of the heavy fermion systems YbT
2 Zn20 (T Ir, Rh and Co) under pressure
K. Matsubayashi; Y. Saiga; T. Matsumoto; Y. Uwatoko
Journal of Physics: Conference Series, 150, 4, 2009, We have measured the electrical resistivity of YbT2Zn 20 (T Ir, Rh) single crystals under pressure up to 2.4 GPa. We found that the resistivity of both compounds shows a pronounced maximum T max under pressure as seen in YbCo2Zn20 at ambient pressure. The temperature Tmax decreases with increasing pressure, reflecting the lowering of the Kondo temperature TK. Low temperature resistivity behaves as expected for a conventional Landau Fermi liquid ρ ρ0 + AT2. The A coefficient is strongly enhanced upon applying pressure and can be related to the Tmax by A-1/2 Tmax. This relation holds for YbT2Zn 20 (T Ir, Rh and Co) compounds in the pressure range investigated here, suggesting the validity of the Fermi liquid description in this system. © 2009 IOP Publishing Ltd.
International conference proceedings - Magnetic Susceptibility Measurement Under High Pressure and Magnetization Measurement of S=1/2 Dioptase Lattice Antiferromagnet
H. Ohta; M. Fujisawa; N. Souda; S. Okubo; E. Ohmichi; T. Sakurai; H. Kikuchi; T. Ono; H. Tanaka; K. Matsubayashi; Y. Uwatoko
25TH INTERNATIONAL CONFERENCE ON LOW TEMPERATURE PHYSICS (LT25), PART 4, IOP PUBLISHING LTD, 150, 2009, Peer-reviwed, Natural mineral Dioptase (Cu6Si6O18 center dot 6H(2)O) is an S=1/2 antiferromagnet with a unique spin network which consists of helical chains along the c axis connected by inter chain exchange interactions. In order to study the ground state of dioptase, we have performed the magnetization measurement for B//c (easy axis) at 1.5 K and have found the spin-flop transition at 13 T. Moreover, the pressure effect of the magnetic susceptibility is investigated up to 1.78 GPa using the SQUID magnetometer where T-N increased while the broad maximum reflecting the low dimensionality of the system decreased by pressure. The results will be discussed in connection with our previous antiferromagnetic resonance (AFMR) measurement results and the phase diagram obtained by Gros et al.
International conference proceedings, English - Superconductivity induced by extremely high pressures in organic Mott-insulator beta '-(BEDT-TTF)(2)IBrCl
M. Kano; K. Uchiyama; H. Taniguchi; M. Hedo; K. Matsubayashi; Y. Uwatoko
25TH INTERNATIONAL CONFERENCE ON LOW TEMPERATURE PHYSICS (LT25), PART 5, IOP PUBLISHING LTD, 150, 2009, Previous research revealed that, at a pressure of 8.2 GPa, beta'-(BEDT-TTF)(2)ICl2 possesses the highest transition temperature (T-C) among the organic conductors[1]. In the present work, transport studies under extremely high pressure of up to 10.0 GPa, using a cubic anvil press are reported for a related material, beta'-(BEDT-TTF)(2)IBrCl which is an organic Mott-insulator in ambient pressure. Superconductivity with the highest T-C (8.5 K, onset) was observed at P = 8.6 GPa.
International conference proceedings, English - Magnetoresistivity of YbCo2Zn20 at low temperature
Yuta Saiga; Kazuyuki Matsubayashi; Tetsuya Fujiwara; Takehiko Matsumoto; Masashi Kosaka; Susumu Katano; Yoshiya Uwatoko
25TH INTERNATIONAL CONFERENCE ON LOW TEMPERATURE PHYSICS (LT25), PART 4, IOP PUBLISHING LTD, 150, 2009, Peer-reviwed, We have studied the electrical resistivity of YbCo2Zn20 under magnetic field up to 18T. With applying magnetic field, the contribution of the Kondo interaction to the electrical resistivity is suppressed and the Fermi liquid regime is extended to higher temperature range. Both the T-2 coefficient of the electrical resistivity A and the residual resistivity rho(0) strongly decrease in magnetic field. From the magnetic variation of the resistivity, it has been found that YbCo2Zn20 is classified as a heavy fermion system with small Kondo temperature of similar to 1.0 K.
International conference proceedings, English - 30aTD-2 Quantum Phase Transition and Superconductivity of the Heavy Fermion System β-YbAlB_4 under Pressure
Tomita T.; Kuga K.; Horie N.; Matsumoto Y.; Nakatsuji S.; Ueda H.; Matsubayashi K.; Matsumoto T.; Uwatoko Y.
Meeting Abstracts of the Physical Society of Japan, The Physical Society of Japan, 64.1.3, 651, 2009
Japanese - Study of the onset of superconductivity in underdoped La2-xSrxCuO4
T. Takami; J-S Zhou; J-G Cheng; J. B. Goodenough; K. Matsubayashi; Y. Uwatoko
NEW JOURNAL OF PHYSICS, IOP PUBLISHING LTD, 11, 595-598, Jan. 2009, Peer-reviwed, The origin of the appearance of superconductivity in the high-transition-temperature (high-T-c) copper oxides has remained a subject of active inquiry. In order to address this issue, we chose La2-xSrxCuO4 as a model system and succeeded in fine controlling the hole concentration around the composition where T-c appears. T-c did not emerge smoothly at a critical hole concentration, x(c). T-c and the absolute value of the Meissner signal below T-c increased progressively with Sr content x > x(c). Measurements of magnetization versus temperature under hydrostatic pressure (P) are also reported for La2-xSrxCuO4, which has no charge reservoir. A dT(c)/dP > 0 found in 0.05 < x < 0.22 peaks out at x approximate to 0.07. Comparison between these results and predictions from existing models for the high-T-c superconductivity has been made.
Scientific journal, English - Observation of Metallic Resistance Down to 56 K in Langmuir-Blodgett Films Based on Ditetradecyldimethylammonium-Au(dmit)(2) Salt
Yasuhiro F. Miura; Masaaki Kitao; Haruki Matsui; Michio Sugi; Masato Hedo; Kazuyuki Matsubayashi; Yoshiya Uwatoko
JAPANESE JOURNAL OF APPLIED PHYSICS, JAPAN SOC APPLIED PHYSICS, 47, 12, 8884-8886, Dec. 2008, Peer-reviwed, A metallic temperature dependence of the resistance of ditetradecyldimethylammonium-Au(dmit)(2) [2C(14)-Au(dmit)(2)] Langmuir-Blodgett (LB) film is observed in a wide temperature range of 56-293 K. While a weak metallic temperature dependence of resistance has been observed down to 216 K in a case where the electrode gap for the measurement is 0.5 mm (500 mu m), an unambiguous metallic behavior is observed down to 56 K when utilizing a narrower interdigitated gap of 5 mu m for the measurement. [DOI: 10.1143/JJAP.47.8884]
Scientific journal, English - Breakdown of magnetic order in Mott insulators with frustrated superexchange interaction
J.-S. Zhou; Y. Uwatoko; K. Matsubayashi; J. B. Goodenough
PHYSICAL REVIEW B, AMER PHYSICAL SOC, 78, 22, 7069-7073, Dec. 2008, Peer-reviwed, Measurements of dc conductivity and ac magnetic susceptibility under pressure to 12 GPa as well as of the crystal structure under pressure were made on antiferromagnetic LaMnO(3) and ferromagnetic LaMn(0.5)Ga(0.5)O(3) crystals. Collapse of magnetic ordering in both crystals has been found at a phase where the static Jahn-Teller distortion is suppressed. These results resolve the question whether a spin-ordered phase will survive if the orbital degree of freedom is released in an e orbital system, a topic of broad current interest.
Scientific journal, English - Superconductivity under High Pressure in LaFeAsO
Hironari Okada; Kazumi Igawa; Hiroki Takahashi; Yoichi Kamihara; Masahiro Hirano; Hideo Hosono; Kazuyuki Matsubayashi; Yoshiya Uwatoko
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, PHYSICAL SOC JAPAN, 77, 11, 2097-2102, Nov. 2008, Peer-reviwed, Electrical resistivity Measurements under high pressures up to 29 GPa were performed for oxypnictide compound LaFeAsO. We found a pressure-induced superconductivity in LaFeAsO. The maximum value of T-c is 21 K at similar to 12 GPa. The pressure dependence of the T-c is similar to those of LaFeAsO1-xFx series reported previously.
Scientific journal, English - High-pressure Studies on Superconducting iron-based LaFeAsO1-xFx , LaFePO and SrFe2As2
Hiroki Takahashi; Hironari Okada; Kazumi Igawa; Kazunobu Arii; Yoichi Kamihara; Satoru Matsuishi; Masahiro Hirano; Hideo Hosono; Kazuyuki Matsubayashi; Yoshiya Uwatoko
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, PHYSICAL SOC JAPAN, 77, 78-83, Nov. 2008, Peer-reviwed, Electrical resistivity and magnetic susceptibility measurements under high pressure were performed on iron-based superconductor LaFePO and LaFeAsO1-xFx system. A steep increase in superconducting transition temperature (T-c) was observed for LaFePO and "optimum-doped" and "over-doped" LaFeAsO1-xFx. Pressure-induced superconductivity was confirmed in undoped LaFeAsO and SrFe2As2 by electrical resistivity measurements under high pressure. X-ray diffraction measurements were also performed under high pressure up to 10 GPa for LaFePO and LaFeAsO1-xFx system, where the anisotropic decrease of the lattice constants was observed with applying pressure.
Scientific journal, English - Excitonic Instability in the Transition from the Black Phase to the Golden Phase of SmS under Pressure Investigated by Infrared Spectroscopy
Takafumi Mizuno; Takuya Iizuka; Shin-ichi Kimura; Kazuyuki Matsubayashi; Keiichiro Imura; Hiroyuki S. Suzuki; Noriaki K. Sato
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, PHYSICAL SOC JAPAN, 77, 11, 895-897, Nov. 2008, Peer-reviwed, We report the pressure-dependent optical reflectivity spectra of a strongly correlated insulator, samarium monosulfide (SmS), in the far- and middle-infrared regions to investigate the origin of the pressure-induced phase transition from the black phase to the golden phase. The energy gap becomes narrow with increasing pressure in the black phase. A valence transition from Sm2+ in the black phase to mainly Sm3+ in the golden phase accompanied by spectral change from insulator to metal were observed at the transition pressure of 0.65 GPa. The black-to-golden phase transition occurs when the energy gap size of black SmS becomes the same as the binding energy of the exciton at the indirect energy gap before the gap closes. This result indicates that the valence transition originates from an excitonic instability.
Scientific journal, English - Critical behavior of the ferromagnetic perovskite BaRuO(3)
J. -S. Zhou; K. Matsubayashi; Y. Uwatoko; C. -Q. Jin; J. -G. Cheng; J. B. Goodenough; Q. Q. Liu; T. Katsura; A. Shatskiy; E. Ito
PHYSICAL REVIEW LETTERS, AMER PHYSICAL SOC, 101, 7, 78-83, Aug. 2008, Peer-reviwed, A thorough study has been made of the physical properties under high pressure of the perovskite BaRuO(3) synthesized under pressure; it includes the critical behavior in the vicinity of T(c) to 1 GPa and the temperature dependences of resistivity and ac magnetic susceptibility up to 8 GPa. The ferromagnetism in BaRuO(3) is suppressed at 8 GPa. Critical fluctuations in the vicinity of T(c) have been found in BaRuO(3) and they are enhanced under pressure. These observations are in sharp contrast to SrRuO(3) where mean-field behavior is found at T(c).
Scientific journal, English - Pressure-induced commensurate magnetic order in multiferroic HoMn2O5
Hiroyuki Kimura; Keisuke Nishihata; Yukio Noda; Naofumi Aso; Kazuyuki Matsubayashi; Yoshiya Uwatoko; Tetsuya Fujiwara
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, PHYSICAL SOC JAPAN, 77, 6, 728-729, Jun. 2008, Peer-reviwed, The pressure-temperature (p-T) phase diagram for microscopic magnetism in the multiferroic compound HoMn2O5 was established using neutron diffraction measurements under a hydrostatic pressure up to 1.25 GPa. At ambient pressure, incommensurate-commensurate-incommensurate magnetic phase transitions occur successively with decreasing temperature. Upon applying pressure, the incommensurate phase at the lowest temperature almost decreases and the commensurate phase appears. The p-T phase diagram established shows excellent agreement with the recently reported p-T dielectric phase diagram, where ferroelectricity is induced by applying pressure. We also found that the p-T magnetic phase diagram is quite similar to the previously obtained magnetic field-temperature phase diagram.
Scientific journal, English - Pressure-induced magnetic transition in a single crystal of YbCo2Zn20
Yuta Saiga; Kazuyuki Matsubayashi; Tetsuya Fujwara; Masashi Kosaka; Susumu Katano; Masato Hedo; Takehiko Matsumoto; Yoshiya Uwatoko
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, PHYSICAL SOC JAPAN, 77, 5, 799-801, May 2008, Peer-reviwed, We have measured the electrical resistivity of a single crystal of YbCo2Zn20 at pressures up to 2.37 GPa and at temperatures from 50 mK to 300 K. Above a critical pressure P. (similar to I GPa), we have found a resistivity anomaly at T-M (similar to 0.15 K at 1 GPa) that increases with the pressure. At the ambient pressure, the system shows a nonmagnetic ground state described by the Fermi-liquid model. The T-2 coefficient of the electrical resistivity A strongly increases with the pressure upon approaching Pc. However, in the vicinity of P,, the temperature dependence of the resistivity deviates from the Fermi-liquid description. These observations suggest that the application of hydrostatic pressure induces a magnetically ordered state for P >= P-c and T <= T-M.
Scientific journal, English - Infrared study on the electronic structure of SmS in the black phase
Shin-ichi Kimura; Takafumi Mizuno; Kazuyuki Matsubayashi; Keiichiro Imura; Hiroyuki S. Suzuki; Noriaki K. Sato
PHYSICA B-CONDENSED MATTER, ELSEVIER SCIENCE BV, 403, 5-9, 805-807, Apr. 2008, Peer-reviwed, We report that the electronic structure of SmS at ambient pressure has been studied by the optical conductivity [sigma(omega)] measurement and by the band structure calculation. The sigma(omega) spectrum has a direct gap structure at 0.4 eV (= 4600 K) but no clear gap structure expected by other experiments appears at 86 meV (= 1000 K). The temperature dependence of the Drude weight, however, indicates the evidence of an indirect gap with the gap size of 1000 K. These results were well explained by a LSDA + U band structure calculation. (c) 2007 Elsevier B.V. All rights reserved.
Scientific journal, English - Transport properties of golden SmS
K. Imura; K. Matsubayashi; H. S. Suzuki; K. Deguchi; N. K. Sato
PHYSICA B-CONDENSED MATTER, ELSEVIER SCIENCE BV, 403, 5-9, 895-897, Apr. 2008, Peer-reviwed, We report electrical resistivity and Hall effect measurements on golden SmS up to a pressure of P similar to 26 kbar. The Hall coefficient at a low temperature shows a drastic decrease above about 13 kbar as a function of P, and a change in sign at a critical pressure P-c2 above which an antiferromagnetically ordered phase appears. We construct a P T phase diagram from the transport properties together with previously reported results of the ac magnetic susceptibility. (c) 2007 Elsevier B.V. All rights reserved.
Scientific journal, English - Superconductivity under High Pressure in LaFeAsO (Condensed matter: electronic structure and electrical, magnetic, and optical properties)
Okada, Hironari; Igawa, Kazumi; Takahashi, Hiroki; KAMIHARA, Yoichi; HIRANO, Masahiro; HOSONO, Hideo; MATSUBAYASHI, Kazuyuki; UWATOKO, Yoshiya
Journal of the Physical Society of Japan, 一般社団法人日本物理学会, 77, 11, 2008
Scientific journal - Effect of nominal composition on transport, optical, magnetic, and thermodynamic properties of SmS single crystals
Kazuyuki Matsubayashi; Keiichiro Imura; Hiroyuki S. Suzuki; Takafumi Mizuno; Shin-ichi Kimura; Takashi Nishioka; Kazuto Kodama; Noriaki K. Sato
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, PHYSICAL SOC JAPAN, 76, 6, 747-750, Jun. 2007, Peer-reviwed, We have grown single crystals of SmS and investigated effects of nominal composition on the electrical resistivity, optical reflectivity, magnetoresistance, dc magnetization, and specific heat. We report that nominally stoichiometric and S-excess samples have an energy gap (E-g) of about 950 (+/-100) K while Sm-excess samples possess E-g of about 1500 (+/-100) K, and further that these values of E-g correlate with the lattice constant. These findings were interpreted as the chemical pressure effect. As an external magnetic field is increased, E-g monotonically decreases albeit in the nonmagnetic black phase, which can be an origin of reported negative magnetoresi stance. The low-temperature specific heat under pressure shows the presence of an intrinsic gamma-term in the golden phase in addition to a spurious gamma-coefficient arising from secondary phases such as SM3S4.
Scientific journal, English - Magnetoresistivity and Hall effect investigations under pressure on SmS
K. Imura; K. Matsubayashi; H. S. Suzuki; K. Deguchi; N. K. Sato
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS, ELSEVIER SCIENCE BV, 310, 2, E54-E56, Mar. 2007, Peer-reviwed, We report magnetoresistivity and Hall resistivity measurements on the black SmS. We observed positive magnetoresistance at low temperatures and negative magnetoresistance in a wide temperature range. The former seems to be ascribed to a magnetic field effect on impurity conduction, and the latter can be attributed to gap-energy reduction by magnetic fields. We also detected hysteresis in the T-dependence of the electrical resistivity under magnetic field. (c) 2006 Elsevier B.V. All rights reserved.
Scientific journal, English - Pseudogap formation near at the border of an insulator-metal transition in SmS
Kazuyuki Matsubayashi; Keiichiro Imura; Hiroyuki S. Suzuki; Genfu Chen; Nobuo Mori; Takashi Nishioka; Kazuhiko Deguchi; Noriaki K. Sato
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, PHYSICAL SOC JAPAN, 76, 3, 7069-7073, Mar. 2007, Peer-reviwed, We measured the thermal expansion and heat capacity of the mixed-valence compound SmS that shows an insulator to metal phase transition under pressure. We report a convincing evidence for the existence of not only an electronic specific heat coefficient gamma but also a Schottky like gap A in the "metal" phase, generally referred to as golden phase. As the pressure increases, gamma steeply increases while A monotonically decreases. Nevertheless, the product gamma Delta/N is kept constant, where N denotes the number of Sm3+ ion. We argue that a novel bound state is formed in golden phase.
Scientific journal, English - Magnetic properties of golden SmS
K. Matsubayashi; K. Imura; H. S. Suzuki; S. Ban; G. F. Chen; K. Deguchi; N. K. Sato
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS, ELSEVIER SCIENCE BV, 310, 2, 408-410, Mar. 2007, Peer-reviwed, We report experimental results of high-pressure AC magnetic susceptibility measurements on SmS, including both a black phase (below a critical pressure P-c1) and a golden phase (above P-c1). We present a convincing evidence for the occurrence of an antiferromagnetically ordered state in the golden phase. (c) 2006 Elsevier B.V. All rights reserved.
Scientific journal, English - Condensed matter: Structure and mechanical and thermal properties-Effect of Nominal Composition on Transport, Optical, Magnetic, and Thermodynamic Properties of SmS Single Crystals
Matsubayashi, Kazuyuki; Imura, Keiichiro; Suzuki; Hiroyuki S.; Mizuno, Takafumi; Kimura, Shin-ichi; Nishioka, Takashi; Kodama, Kazuto; Sato; Noriaki K.
Journal of the Physical Society of Japan, [Tokyo]: The Society,[1946-, 76, 6, 64601-64601, 2007
Scientific journal - Competitive coexistence of superconductivity with antiferromagnetism in CeRhIn5
G. F. Chen; K. Matsubayashi; S. Ban; K. Deguchi; N. K. Sato
PHYSICAL REVIEW LETTERS, AMERICAN PHYSICAL SOC, 97, 1, 595-598, Jul. 2006, Peer-reviwed, We carried out ac magnetic susceptibility measurements under pressures P on the heavy fermion antiferromagnet CeRhIn5. We report bulk superconductivity (SC) at ambient pressure with a transition temperature T-c similar or equal to 90 mK. The degraded SC in a powdered or polished sample was restored by annealing, showing that the SC state is sensitive to inhomogeneity. In a coexistence region of the SC with antiferromagnetism (AF), we find that T-c(P)T-n(N)(P)(1-n)=const where T-N indicates a Neel temperature and n denotes a ratio of electronic specific heat coefficients below and above T-N, indicating the competition of the SC and the AF for states at the Fermi surface.
Scientific journal, English - Specific heat measurement in golden-SmS
K Matsubayashi; K Imura; HS Suzuki; G Chen; NK Sato
PHYSICA B-CONDENSED MATTER, ELSEVIER SCIENCE BV, 378-80, 726-727, May 2006, Peer-reviwed, We have measured the specific heat of SmS single crystals under pressure. We report that a gamma-term in the golden phase can be represented as the sum of intrinsic and extrinsic contributions, and argue that there seems to be a relation between the intrinsic gamma and a pseudo gapenergy Delta as gamma Delta = const. (c) 2006 Elsevier B.V. All rights reserved.
Scientific journal, English - Thermal expansion study on high-pressure phases of SmS
K Imura; K Matsubayashi; HS Suzuki; T Nishioka; N Mori; NK Sato
PHYSICA B-CONDENSED MATTER, ELSEVIER SCIENCE BV, 378-80, 728-729, May 2006, Peer-reviwed, We have measured the thermal expansion coefficient alpha(L)(T) of SmS under pressure up to 21.6 kbar. In the golden phase, an excitation gap A inferred from alpha(L)(T) decreases with increasing pressure. When the system enters the metallic phase from the golden phase, A collapses suddenly to zero, and simultaneously, a huge sharp anomaly appears in the alpha(L)(T) curve, reflecting the magnetic phase transition. (c) 2006 Elsevier B.V. All rights reserved.
Scientific journal, English - Competitive coexistence of superconductivity with antiferromagnetism in CeRhIn 5
Chen, GF; Matsubayashi, K.; Ban, S.; Deguchi, K.; Sato, NK
Physical review letters, American Physical Society, 97, 1, 017005-017005, 2006
Scientific journal - Single crystal growth of "pure" SmS
K Matsubayashi; HS Suzuki; K Imura; T Nishioka; NK Sato
PHYSICA B-CONDENSED MATTER, ELSEVIER SCIENCE BV, 359, 151-153, Apr. 2005, Peer-reviwed, We have prepared single crystals of SmS under various conditions, and studied sample dependence on the specific heat and the electrical resistivity. Some samples exhibit a huge anomaly in the temperature dependence of the specific heat at low temperatures. We show that the anomaly can be ascribed to secondary phases and will give rise to a spurious gamma T term in the golden phase. (c) 2005 Elsevier B.V. All rights reserved.
Scientific journal, English - Pressure-induced magnetic phase transition in gold-phase SmS
Y Haga; J Derr; A Barla; B Salce; G Lapertot; Sheikin, I; K Matsubayashi; NK Sato; J Flouquet
PHYSICAL REVIEW B, AMER PHYSICAL SOC, 70, 22, Dec. 2004, Peer-reviwed, Electrical resistivity and specific heat of SmS in its gold phase have been investigated. Above P-Delta=2 GPa, the resistivity is characteristic of a metallic heavy fermion compound. Ac calorimetry points out a phase transition with the occurrence of a new ground state. Analyses of the resistivity and of the specific heat and comparison with a microscopic probe (Sm-149 nuclear forward scattering) allow us to identify the onset of antiferromagnetism. Discussion will be made on the interplay of gap closing (P<P-Delta), long-range magnetism (P>P-Delta), and valence state.
Scientific journal, English - Thermal expansion measurement under pressure on SmS
K. Matsubayashi; T. Nishioka; N. K. Sato
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS, ELSEVIER SCIENCE BV, 272, SUPPL. 1, E277-E278, May 2004, Peer-reviwed, We measured the thermal expansion of a single-crystalline SmS sample under pressure along (100) direction from 4.2 K to room temperature. We have found that the thermal expansion coefficient a shows a broad minimum in the so-called golden phase and can be described by a Schottky-type anomaly with an energy gap D: We have revealed that D decreases with increasing pressure and possibly disappears around P-M similar to 20 kbar, above which the system is evidently in the metal phase. (C) 2003 Elsevier B.V. All rights reserved.
Scientific journal, English - Extrinsic origin of high-temperature ferromagnetism in CaB6
K Matsubayashi; M Maki; T Moriwaka; T Tsuzuki; T Nishioka; CH Lee; A Yamamoto; T Ohta; NK Sato
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, PHYSICAL SOC JAPAN, 72, 8, 2097-2102, Aug. 2003, Peer-reviwed, The discovery of ferromagnetism in CaB6 doped with La was surprising, because there is no magnetic element in the compound nevertheless the system involved a ferromagnetic Curie temperature as high as 600 K. In order to resolve the origin of the ferromagnetism, we have made magnetization measurements and chemical analysis of CaB6 and LaB6 samples synthesized under various conditions. We have found that the ferromagnetism disappears almost completely by the acid etching, and that there is strong correlation between the magnitude of reduced magnetization and the iron concentration involved in the acid. Therefore we conclude that the ferromagnetism is of extrinsic origin and can be ascribed to iron impurity phases, probably FeB and Fe2B that have nearly the same Curie temperature as CaB6. We suggest that these iron impurities originate from the crucible used in the synthesis. Furthermore we have measured the thermoelectric power at high temperatures including the Curie temperature. There seems to be no relation between the appearance of the ferromagnetism and the transport properties, and no evidence for the bulk ferromagnetism has been observed.
Scientific journal, English - Insulator-metal transition studied by heat capacity measurements on SmS
K Matsubayashi; H Mukai; T Tsuzuki; T Nishioka; NK Sato
PHYSICA B-CONDENSED MATTER, ELSEVIER SCIENCE BV, 329, II, 484-485, May 2003, Peer-reviwed, We have measured the specific heat of SmS at pressures up to similar to7.5 kbar. We have observed that the electronic specific heat coefficient gamma shows a steep increase at around P(c)similar to3.5 kbar, which corresponds to an insulator-metal phase transition. In the metal phase above P-c, we have found that gamma reaches 100 mJ/mol K-2, indicating a strongly correlated metallic state. In the insulator phase, on the other hand, we have observed an anomaly in the temperature dependence of the specific heat around 1 K, which seems to survive in the metal phase. (C) 2002 Elsevier Science B.V. All rights reserved.
Scientific journal, English - Magnetic properties - Parasitic ferromagnetism in a hexaboride? Reply
DP Young; Z Fisk; JD Thompson; HR Ott; SB Oseroff; RG Goodrich
NATURE, NATURE PUBLISHING GROUP, 420, 6912, 144-144, Nov. 2002, Peer-reviwed
Scientific journal, English
MISC
- Thermoelectric power and ac specific heat measurements of YbRh2Zn20 under pressure and at low temperatures
鈴木雄大; 工藤一輝; 橘高俊一郎; 辺土正人; 上床美也; 松林和幸
2024, 日本物理学会講演概要集(CD-ROM), 79, 1, 2189-079X, 202402232111916986 - Discovery of a low-symmetrized phase including a superconducting phase in CuRh2Se4 under high pressure
江見方敏; 小島慶太; 塩見学; 片山尚幸; 松林和幸; 門林宏和; 河口沙織; 平尾直久; 澤博
2023, 日本物理学会講演概要集(CD-ROM), 78, 1, 2189-079X, 202302223858875843 - 励起子絶縁体から超伝導への高圧力による制御
松林和幸; 有馬寛人; 有馬寛人
2022, 固体物理, 57, 8, 0454-4544, 202202233763321290 - Thermal properties of heavy fermion YbCo2Zn20 at low temperatures and pressures
鈴木雄大; 工藤一輝; 辺土正人; 上床美也; 松林和幸
2022, 日本物理学会講演概要集(CD-ROM), 77, 2, 2189-079X, 202302226730000598 - Magnetocaloric effect in Gd5Ge4
高野尚志; 上原政智; 石渡信吾; 梅原出; 上床美也; 郷地順; 松林和幸
2021, 日本物理学会講演概要集(CD-ROM), 76, 1, 2189-079X, 202102241907221091 - Non-Fermi liquid behavior above the critical pressure for the suppression of ferro-quadrupole order in PrTi2Al20
山本洸凪; 元山史都; 曾我部尚希; 磯前貴央; 酒井明人; 中辻知; 北川健太郎; 上床美也; 松林和幸
2021, 日本物理学会講演概要集(CD-ROM), 76, 1, 2189-079X, 202102290781475469 - Hall effect measurement of narrow gap semiconductor Ta2NiS5 under pressure
有馬寛人; 片山尚幸; 澤博; 野原実; LU Y. F.; 北川健太郎; 高木英典; 高木英典; 上床美也; 松林和幸
2021, 日本物理学会講演概要集(CD-ROM), 76, 2, 2189-079X, 202202252647498997 - Effect of magnetic field and pressure on quadrupole order in PrRu2Sn2Zn18
山本洸凪; 駒形貴裕; 脇舎和平; 梅原出; 郷地順; 上床美也; 松林和幸
2021, 日本物理学会講演概要集(CD-ROM), 76, 2, 2189-079X, 202202259102026798 - Temperature-pressure phase diagrams of BiS2-based layered compounds
有馬寛人; YUAN Yahua; 内藤康氏; 工藤一輝; 矢藤優佑; JHA Rajveer; 後藤陽介; 水口佳一; 松田達麿; 青木勇二; 松林和幸
2020, 日本物理学会講演概要集(CD-ROM), 75, 1, 2189-079X, 202002217419329839 - Thermoelectric power of YbCo2Zn20 under pressure, low temperature and magnetic field
工藤一輝; 内藤康氏; 有馬寛人; 上床美也; 松林和幸
2020, 日本物理学会講演概要集(CD-ROM), 75, 1, 2189-079X, 202002231861650558 - Effect of pressure on quadrupole order in PrRu2Sn2Zn18
山本洸凪; 駒形貴裕; 脇谷和平; 梅原出; 郷地順; 上床美也; 松林和幸
2020, 日本物理学会講演概要集(CD-ROM), 75, 1, 2189-079X, 202002219927419644 - Heavy fermion superconductivity on PrTi2Al20 under pressure
山本洸凪; 元山史都; 曾我部尚希; 磯前貴央; 酒井明人; 酒井明人; 中辻知; 中辻知; 北川健太郎; 上床美也; 松林和幸
2020, 日本物理学会講演概要集(CD-ROM), 75, 2, 2189-079X, 202102213641693473 - 高圧下における熱電能測定装置の開発
内藤康氏; 工藤一輝; 有馬寛人; 辺土正人; 松林和幸
2019, 日本物理学会講演概要集(CD-ROM), 74, 1, 2189-079X, 201902273213727749 - LaOBiPbS3およびLa2O2Bi3AgS6における圧力誘起超伝導と高圧下における電気輸送特性
内藤康氏; 工藤一輝; 有馬寛人; 辺土正人; 水口佳一; JHA Rajveer; 後藤陽介; 松田達磨; 青木勇二; 松林和幸
2019, 日本物理学会講演概要集(CD-ROM), 74, 2, 2189-079X, 202002280014690761 - PrTi2Al20における高圧下交流比熱測定
星竜二; 元山史都; 桑田凌; 橘高俊一郎; 上床美也; 曽我部尚希; 酒井明人; 中辻知; 北川健太郎; 松林和幸
2019, 日本物理学会講演概要集(CD-ROM), 74, 1, 2189-079X, 201902211426648748 - 高圧下におけるTa2NiSe5の輸送特性
有馬寛人; 内藤康氏; 工藤一輝; 片山尚幸; 澤博; 野原実; LU Y. F.; 北川健太郎; 高木英典; 高木英典; 上床美也; 松林和幸
2019, 日本物理学会講演概要集(CD-ROM), 74, 1, 2189-079X, 201902279364896124 - 高圧下における熱電能測定法の開発とYbCo2Zn20への応用
工藤一輝; 内藤康氏; 有馬寛人; 上床美也; 松林和幸
2019, 日本物理学会講演概要集(CD-ROM), 74, 2, 2189-079X, 202002263848791914 - 重い電子系化合物Yb(Co1-xIrx)2Zn20の物性
瑞慶覧長星; 佐藤信; 高村治希; 小林理気; 阿曽尚文; 植田大地; 池田陽一; 吉田雅洋; 吉澤英樹; 松林和幸; 郷地順; 上床美也
2018, 日本物理学会講演概要集(CD-ROM), 73, 1, 2189-079X, 201802287045064726 - 励起子絶縁体候補物質Ta2NiSe5における高圧下ホール効果
有馬寛人; 片山尚幸; 野原実; LU Y.F.; 高木英典; 高木英典; 上床美也; 松林和幸
2018, 日本物理学会講演概要集(CD-ROM), 73, 1, 2189-079X, 201802262280316268 - 高圧下におけるPrTi2Al20の超伝導と非フェルミ液体的振る舞い
元山史都; 辻本真規; 酒井明人; 中辻知; 北川健太郎; 上床美也; 松林和幸
2018, 日本物理学会講演概要集(CD-ROM), 73, 1, 2189-079X, 201802283952025671 - YbCo2Ge4における非フェルミ液体的挙動とメタ磁性の圧力効果
桑田凌; 岩谷誠; 北川健太郎; 上床美也; 松林和幸
2018, 日本物理学会講演概要集(CD-ROM), 73, 1, 2189-079X, 201802276278490499 - Ta2NiSe5の相図における静水圧と異方的圧力効果の比較
有馬寛人; 片山尚幸; 野原実; LU Y.F.; 北川健太郎; 高木英典; 高木英典; 上床美也; 松林和幸
2018, 日本物理学会講演概要集(CD-ROM), 73, 2, 2189-079X, 201802214578403581 - PrTi2Al20の高圧下で顕在化する非フェルミ液体的挙動と超伝導の相関
元山史都; 曽我部尚希; 酒井明人; 中辻知; 北川健太郎; 上床美也; 松林和幸
2018, 日本物理学会講演概要集(CD-ROM), 73, 2, 2189-079X, 201802223236619100 - YbCo2Ge4の圧力-温度-磁場相図
桑田凌; 岩谷誠; 北川健太郎; 上床美也; 松林和幸
2018, 日本物理学会講演概要集(CD-ROM), 73, 2, 2189-079X, 201802285087031309 - Sample preparation of SmPtSi2and its fundamental properties
Yamaguchi S; Takahashi E; Nakano T; Takeda N; Matsubayashi K; Uwatoko Y; Uhlirova K; Pronkleska J; Sechovsky V
The Physical Society of Japan, 2018, Meeting Abstracts of the Physical Society of Japan, 73, 0, 1714-1714, Japanese, 130007735434 - Ta2NiSe5の圧力誘起層スライド転移
中埜彰俊; 菅原健人; 田村慎也; 片山尚幸; 松林和幸; 岡田卓; 上床美也; 宗像孝司; 中尾朗子; 佐賀山基; 熊井玲児; 前島尚行; 町田晃彦; 綿貫徹, 澤博
25 Oct. 2017, 高圧討論会講演要旨集, 58th, 133, Japanese, 0917-6373, 201702252715718316 - 励起子絶縁体候補物質Ta2NiSe5における高圧下電気抵抗とホール効果
有馬寛人; 片山尚幸; 野原実; LU Y. F.; 高木英典; 高木英典; 上床美也; 松林和幸
2017, 日本物理学会講演概要集(CD-ROM), 72, 2, 2189-079X, 201702279373188260 - YbCo2Ge4における圧力誘起磁気秩序
桑田凌; 岩谷誠; 北側健太郎; 上床美也; 松林和幸
2017, 日本物理学会講演概要集(CD-ROM), 72, 2, 2189-079X, 201702229245305115 - PrTi2Al20における強四極子秩序と超伝導の圧力効果
元山史都; 辻本真規; 酒井明人; 中辻知; 北川健太郎; 上床美也; 松林和幸
2017, 日本物理学会講演概要集(CD-ROM), 72, 2, 2189-079X, 201702254317104221 - FeSe純良単結晶における高圧下電気抵抗率測定
松浦康平; 水上雄太; 下澤雅明; 松林和幸; 山下穣; 上床美也; 綿重達哉; 笠原成; SUN J. P; YE G. Z; YAN J. Q; SALES B. C; CHENG J.‐G; 松田祐司; 芝内孝禎
22 Mar. 2016, 日本物理学会講演概要集(CD-ROM), 71, 1, ROMBUNNO.22ABQ‐4, Japanese, 2189-079X, 201602203795919389 - Yb3d‐2p共鳴X線発光分光によるYbCo2Zn20およびYbCo2Ge4の電子状態の研究
河村直己; 水牧仁一朗; 魚住孝幸; 藤内博紀; 松林和幸; 岩谷誠; 北川健太郎; 広瀬雄介; 本多史憲; 渡辺真仁
22 Mar. 2016, 日本物理学会講演概要集(CD-ROM), 71, 1, ROMBUNNO.21PBM‐4, Japanese, 2189-079X, 201602296688110192 - 22pBL-5 ^<63>Cu-NMR studies of pressure-induced superconductivity in a spin-ladder cuprate Sr_<1.4>Ca_<12.6>Cu_<24>O_<41>
Hisada A.; Koyama K.; Saito T.; Magishi K.; Fujiwara N.; Matsubayashi K.; Uwatoko Y.; Deng G.; Pomjakushina E.; Conder K.; Radheep D. Mohan; Thiyagarajan R.; Esakkimuthu S.; Arumugam S.
The Physical Society of Japan (JPS), 2016, Meeting Abstracts of the Physical Society of Japan, 71, 2453-2453, Japanese, 2189-079X, 110010058392, AA12721570 - 22aBM-10 Point-Contact spectroscopic study on Antiferromagnetic Heavy fermion compounds CeIn_3
Motoyama G.; Uwatoko Y.; Yamaguchi A.; Matsubayashi K.; Ogawa S.; Mutou T.; Miyoshi K.; Nishigori S.; Fujiwara K.; Sumiyama A.
The Physical Society of Japan, 2016, Meeting Abstracts of the Physical Society of Japan, 71, 0, 2369-2369, Japanese, 2189-079X, 110010058308, AA12721570 - Linear dichroism of Yb 3d core level photoelectron spectrum in orthorhombic compound YbCo2Ge4
Kuga K.; Kadono T.; Imai S.; Yamasaki A.; Tamasaku K.; Yabashi M.; Ishikawa T.; Kitagawa K.; Matsubayashi K.; Kiss T.; Kanai Y.; Fujiwara H.; Fujioka S.; Yamagami K.; Yomosa H.; Aoyama Y.; Sekiyama A.; Higashiya A.Yb 3d光電子スペクトルは、光励起されたYb 3dホールと4f電子の間の相互作用により多重項分裂し、その相対強度は光の進行方向に対する4f電子軌道断面と偏光方向に応じて異なる。この性質を利用し、励起光の入射方向と偏光方向を制御することで、4f電子軌道、つまり結晶場波動関数を決定することが出来る。そこで、我々は結晶構造に斜方晶の対称性を持つ量子臨界物質YbCo_2_Ge_4_に対し、硬X線励起Yb 3d光電子スペクトル線二色性を25 Kの温度で測定した。本発表では、線二色性のシミュレーション結果と比較し、結晶場基底状態の推定を行う。
, The Physical Society of Japan, 2016, Meeting Abstracts of the Physical Society of Japan, 71, 2, 2120-2120, Japanese, 2189-079X, 2189-0803, 201602212933839050, 130006244841 - メタ磁性体MnCo0.92Fe0.08Ge化合物の磁気と構造特性
大園康介; 三井好古; 廣井政彦; 梅津理恵; 高橋弘紀; 松林和幸; 上床美也; 小山佳一
2016, 東北大学金属材料研究所強磁場超伝導材料研究センター年次報告, 2015, 201602247743371619 - EuPd2Si2とEuPd2Ge2の単結晶育成と価数転移
赤嶺拡; 安次富洋介; 天児寧; 中島美帆; 竹内徹也; 松林和幸; 上床美也; 本多史憲; 辺土正人; 仲間隆男; 大貫惇睦
24 Sep. 2015, 日本物理学会講演概要集(CD-ROM), 70, 2, ROMBUNNO.19ADA‐2, Japanese, 2189-079X, 201602220267976772 - EuCu9Sn4とEuZn13における圧力下電気抵抗測定
佐藤翔子; 広瀬雄介; 都丸駿; 太田俊平; 倉橋秀平; 竹内徹也; 本多史憲; 本間佳哉; LI D.X; 青木大; 松林和幸; 上床美也; 芳賀芳範; 摂待力生
24 Sep. 2015, 日本物理学会講演概要集(CD-ROM), 70, 2, ROMBUNNO.17APS-75, Japanese, 2189-079X, 201602219499484762 - 18aDB-2 The electronic phase diagram in FeSe under high pressure
Matsuura K; Mizukami Y; Shimozawa M; Matsubayashi K; Yamashita M; Uwatoko Y; Wolf T; v. Lohneysen H; Watashige T; Kasahara S; Matsuda Y; Shibauchi T
The Physical Society of Japan (JPS), 16 Sep. 2015, 日本物理学会講演概要集, 70, 2, Japanese, 2189-079X, 110010029586 - Eu化合物の価数転移と重い電子状態
大貫惇睦; 仲村愛; 本多史憲; 佳山周永; 加賀山朋子; 清水克哉; 芳賀芳範; 松林和幸; 上床美也; 辺土正人; 仲間隆男
24 Mar. 2015, 日本物理学会講演概要集(CD-ROM), 70, 1, ROMBUNNO.22PBA-11, Japanese, 2189-079X, 201502212419292114 - CeCu9Sn4及び関連物質の単結晶育成と磁性
佐藤翔子; 広瀬雄介; 都丸駿; 太田俊平; 倉橋秀平; 竹内徹也; 本多史憲; 本間佳哉; LI D.X; 青木大; 松林和幸; 上床美也; 芳賀芳範; 摂待力生
24 Mar. 2015, 日本物理学会講演概要集(CD-ROM), 70, 1, ROMBUNNO.22APS-30, Japanese, 2189-079X, 201502218111501136 - 24aDC-4 Pressure effect on superconductivity and anisotropy of electrical resistivity in two-leg ladder cuprate Sr_<1.4>Ca_<12.6>Cu_<24>O_<41>
Hisada A.; Koyama K.; Saito T.; Magishi K.; Jinguang C.; Matsubayashi K.; Uwatoko Y.; Fujiwara N.; Deng G.; Pomjakushina E.; Conder K.; Radheep D. Mohan; Thiyagarajan R.; Esakkimuthu S.; Arumugam S.
The Physical Society of Japan (JPS), Mar. 2015, Meeting Abstracts of the Physical Society of Japan, 70, 1, 2367-2367, Japanese, 2189-079X, 110009991671, AA12721570 - Ni50-xCoxMn31.5Ga18.5の高圧効果
安達義也; 池田大地; 松田有矢; 鹿又武; 松林和幸; 上床美也; 梅津理恵; 許きょう; 貝沼亮介; 片岡光生
2015, 日本金属学会講演概要(CD-ROM), 156th, 2433-3093, 201502234587007940 - 19aPS-10 NMR study in a spin-ladder cuprate Sr_<1.4>Ca_<12.6>Cu_<24>O_<41> under pressure
Hisada A.; Koyama K.; Saito T.; Magishi K.; Fujiwara N.; Matsubayashi K.; Uwatoko Y.; Deng G.; Pomjakushina E.; Conder K.; Radheep D. Mohan; Thiyagarajan R.; Esakkimuthu S.; Arumugam S.
The Physical Society of Japan (JPS), 2015, Meeting Abstracts of the Physical Society of Japan, 70, 2104-2104, Japanese, 2189-079X, 110010029699, AA12721570 - 17aPS-24 Point Contct Spectroscopy of Ce compound with metamagnetism III
Ogawa S.; Uwatoko Y.; Motoyama G.; Matsubayashi K.; Yamaguchi A.; Fujiwara K.; Miyoshi K.; Nishigori S.; Mutou T.; Sumiyama A.
The Physical Society of Japan, 2015, Meeting Abstracts of the Physical Society of Japan, 70, 0, 1820-1820, Japanese, 2189-079X, 110010029434, AA12721570 - 22aPS-86 Point Contct Spectroscopy of Ce compound with metamagnetism II
Ogawa S.; Uwatoko T.; Motoyama G.; Matsubayashi K.; Miyoshi K.; Nishigori S.; Fujiwara K.; Mutou T.; Yamaguchi A.; Sumiyama A.
The Physical Society of Japan, 2015, Meeting Abstracts of the Physical Society of Japan, 70, 0, 2176-2176, Japanese, 2189-079X, 110009990221, AA12721570 - 16aPS-13 Observation of magnetic field induced martensitic transformation on MnCo0.92Fe0.08Ge
Ozono K.; Mitsui Y.; Hiroi M.; Koyama K.; Umetsu R. Y.; Matsubayashi K.; Uwatoko Y.
The Physical Society of Japan (JPS), 2015, Meeting Abstracts of the Physical Society of Japan, 70, 719-719, Japanese, 2189-079X, 110010028795, AA12721570 - 放射光X線回折を用いた励起子絶縁体の構造解析
中埜彰俊; 鬼頭俊介; 片山尚幸; 佐賀山基; 熊井玲児; 松林和幸; 岡田卓; 上床美也; 宗像孝司; 中尾朗子; 高木英典; 高木英典; 市村晃一; 丹田聡; 澤博
2015, 日本物理学会講演概要集(CD-ROM), 70, 1, 2189-079X, 201502205037367800 - MnCo0.92Fe0.08Ge合金の強磁場X線回折測定による磁場誘起マルテンサイト変態の観測
大園康介; 三井好古; 高橋弘紀; 梅津理恵; 廣井政彦; 松林和幸; 上床美也; 小山佳一
2015, 東北大学金属材料研究所強磁場超伝導材料研究センター年次報告, 2014, 201502205426270383 - 圧力誘起超伝導体CePtSi2単結晶の圧力下ゼーベック係数
山田和弘; 佐藤晴紀; 松本絋祐; 加瀬直樹; 中野智仁; 武田直也; 松林和幸; 上床美也
2015, 高圧討論会講演要旨集, 56th, 0917-6373, 201502219209077274 - High-pressure effects in anti-post-perovskite superconductors V(3)PnN(x) (Pn = P, As) (vol 89, 144510, 2014)
B. S. Wang; J. -G. Cheng; K. Matsubayashi; Y. Uwatoko; K. Ohgushi
AMER PHYSICAL SOC, Oct. 2014, PHYSICAL REVIEW B, 90, 13, English, Others, 1098-0121, 1550-235X, WOS:000344025100004 - 7aPS-93 Magnetic properties of Ho_<1-x>Gd_xRh_2Si_2
Morita T.; Fujiwara T.; Matsubayashi K.; Uwatoko Y.; Shigeoka T.
The Physical Society of Japan (JPS), 22 Aug. 2014, Meeting abstracts of the Physical Society of Japan, 69, 2, 253-253, Japanese, 1342-8349, 110009887104, AA11439205 - 7aPS-95 Magnetic properties of polymorphic compounds RIr_2Si_2 (R=Gd,Tb)single crystal
Nakata T.; Fujiwara T.; Matsubayashi K.; Uwatoko Y.; Shigeoka T.
The Physical Society of Japan (JPS), 22 Aug. 2014, Meeting abstracts of the Physical Society of Japan, 69, 2, 253-253, Japanese, 1342-8349, 110009887106, AA11439205 - 7aPS-97 Magnetic properties of polymorphic compounds ErIr_2Si_2
Tabata K.; Fujiwara T.; Matsubayashi K.; Uwatoko Y.; Shigeoka T.
The Physical Society of Japan (JPS), 22 Aug. 2014, Meeting abstracts of the Physical Society of Japan, 69, 2, 254-254, Japanese, 1342-8349, 110009887108, AA11439205 - 7aPS-94 Magnetic property of Ho_<1-x>Y_xRh_2Si_2 crystal
Hujii Y.; Fujiwara T.; Matsubayashi K.; Uwatoko Y.; Shigeoka T.
The Physical Society of Japan (JPS), 22 Aug. 2014, Meeting abstracts of the Physical Society of Japan, 69, 2, 253-253, Japanese, 1342-8349, 110009887105, AA11439205 - 7aPS-139 Magnetism of triangular lattice antiferromagnet NaMn(Acac)_3benzene
Karaki Y.; Halim Mario; Suzuki S.; Matsubayashi K.; Uwatoko Y.
The Physical Society of Japan (JPS), 22 Aug. 2014, Meeting abstracts of the Physical Society of Japan, 69, 2, 263-263, Japanese, 1342-8349, 110009887146, AA11439205 - 7pBD-10 A new iron arsenide with three dimensional network structure of FeAs plane
Katayama N.; Sawa H.; Matsubayashi K.; Uwatoko Y.
The Physical Society of Japan (JPS), 22 Aug. 2014, Meeting abstracts of the Physical Society of Japan, 69, 2, 336-336, Japanese, 1342-8349, 110009887403, AA11439205 - 7pBD-13 Pressure Induced Superconductivity in Antiferromagnetic CrAs
Cheng J.; Matsubayashi K.; Uwatoko Y.; Wu W.; Kong P.; Lin F.; Jin C.; Wang N.; Luo J.; Matsuda M.
The Physical Society of Japan (JPS), 22 Aug. 2014, Meeting abstracts of the Physical Society of Japan, 69, 2, 337-337, Japanese, 1342-8349, 110009887406, AA11439205 - 10aBD-10 Quantum criticality of Yb124 compound with new structure probed by ^<59>Co-NMR
Kishimoto Y.; Kitagawa K.; Iwatani M.; Nishioka T.; Matsumura M.; Maki S.; Yamaura J-I.; Hattori T.; Ishida K.; Matsubayashi K.; Uwatoko Y.
The Physical Society of Japan (JPS), 22 Aug. 2014, Meeting abstracts of the Physical Society of Japan, 69, 2, 450-450, Japanese, 1342-8349, 110009887843, AA11439205 - 8aPS-75 Quantum criticality of Yb-124 compound with a new structure observed by bulk and NMR experiments
Kitagawa K.; Iwatani M.; Kishimoto Y.; Matsumura M.; Maki S.; Yamaura J-I.; Hattori T.; Ishida K.; Matsubayashi K.; Uwatoko Y.
The Physical Society of Japan (JPS), 22 Aug. 2014, Meeting abstracts of the Physical Society of Japan, 69, 2, 374-374, Japanese, 1342-8349, 110009887556, AA11439205 - 8aPS-100 X-ray absorption and its resonant X-ray emission spectrum associated with 2p→4f electric quadrupole transition for rare-earth elements
Kawamura N.; Nitta K.; Mizumaki M.; Ishimatsu N.; Matsubayashi K.; Matsuda Y. H.; Naito T.; Fujishiro H.; Uwatoko Y.; Ohara S.; Watanabe S.
The Physical Society of Japan (JPS), 22 Aug. 2014, Meeting abstracts of the Physical Society of Japan, 69, 2, 380-380, Japanese, 1342-8349, 110009887580, AA11439205 - 7aBK-7 High quality single crystal growth and electronic states of noncentro-symmetric EuTGe_3 (T: transition metals)
Hedo M.; Uejo T.; Akamine H.; Tomori K.; Nakamura A.; Nakashima M.; Amako Y.; Matsubayashi K.; Uwatoko Y.; Nakama T.; Onuki Y.
The Physical Society of Japan (JPS), 22 Aug. 2014, Meeting abstracts of the Physical Society of Japan, 69, 2, 329-329, Japanese, 1342-8349, 110009887385, AA11439205 - 7aBK-4 High-Quality Single Crystal Growth and Fermi Surfaces of Ferromagnet EuPd_2
Onuki Y.; Nakamura A.; Akamine H.; Takeuchi T.; Tatetsu Y.; Maehira T.; Honda F.; Matsubayashi K.; Uwatoko Y.; Hedo M.; Nakama T.
The Physical Society of Japan (JPS), 22 Aug. 2014, Meeting abstracts of the Physical Society of Japan, 69, 2, 329-329, Japanese, 1342-8349, 110009887382, AA11439205 - 7aBG-2 Pressure-induced superconductivity on possible excitonic insulating compound Ta_2NiSe_5
Matsubayashi K.; Yamanaka R.; Hisada A.; Katayama N.; Nohara M.; Takagi H.; Uwatoko Y.
The Physical Society of Japan (JPS), 22 Aug. 2014, Meeting abstracts of the Physical Society of Japan, 69, 2, 321-321, Japanese, 1342-8349, 110009887352, AA11439205 - かご状構造を有するR5Ir6Sn18(R=Tb,Dy,Ho,Er,Tm,Yb)の磁性と超伝導
増村昌三; 穴田泰士; 加瀬直樹; 中野智仁; 武田直也; 松林和幸; 上床美也
22 Aug. 2014, 日本物理学会講演概要集, 69, 2, 361, Japanese, 1342-8349, 201402217875570995 - 27aPS-48 Magnetic States of Mn_2Sb-based Metamagnetic Materials under High Pressures
Matsumoto Yoshihiro; Koyama Keiichi; Matsubayashi Kazuyuki; Uwatoko Yoshiya
The Physical Society of Japan (JPS), 05 Mar. 2014, Meeting abstracts of the Physical Society of Japan, 69, 1, 485-485, Japanese, 1342-8349, 110009835298, AA11439205 - 28aBE-1 Pressure dependence of the electric resistivity in the heavy fermion system α-YbAlB_4
Shimura Y.; Tomita T.; Matsubayashi K.; Uwatoko Y.; Zeng Bin; Balicas Luis; Nakatsuji S.
The Physical Society of Japan (JPS), 05 Mar. 2014, Meeting abstracts of the Physical Society of Japan, 69, 1, 582-582, Japanese, 1342-8349, 110009835653, AA11439205 - 27aCJ-2 de Haas-van Alphen effect and pressure effect of EuTIn_4 (T: Ni, Pd, Pt)
Hedo M.; Hiranaka Y.; Nakamura A.; Nakama T.; Onuki Y.; Harima H.; Honda F.; Takeuchi T.; Haga Y.; Matsubayashi K.; Uwatoko Y.
The Physical Society of Japan (JPS), 05 Mar. 2014, Meeting abstracts of the Physical Society of Japan, 69, 1, 549-549, Japanese, 1342-8349, 110009835527, AA11439205 - 27pCE-10 Pressure effects on iron-based ladder compound Ba_<1-x>Cs_xFe_2Se_3
Hawai T.; Matsubayashi K.; Ohgushi K.; Nambu Y.; CHENG Jinguang; Uwatoko Y.; Sato T. J.; Yoshizawa H.
The Physical Society of Japan (JPS), 05 Mar. 2014, Meeting abstracts of the Physical Society of Japan, 69, 1, 563-563, Japanese, 1342-8349, 110009835576, AA11439205 - 27pBE-10 Magnetic field-temperature phase diagrams under pressure in antiferroquadrupolar PrV_2Al_2
Matsubayashi K.; Suzuki J.; Tsujimoto M.; Sakai A.; Nakatsuji S.; Kitagawa K.; Uwatoko Y.
The Physical Society of Japan (JPS), 05 Mar. 2014, Meeting abstracts of the Physical Society of Japan, 69, 1, 555-555, Japanese, 1342-8349, 110009835553, AA11439205 - 28aPS-30 Ce L3-edge X-ray absorption measurements at high pressure in Ce_2NiGa_<12>
Kawamura N.; Matsubayashi K.; Ishimatsu N.; Mizumaki M.; Uwatoko Y.; Ohara S.; Watanabe S.
The Physical Society of Japan (JPS), 05 Mar. 2014, Meeting abstracts of the Physical Society of Japan, 69, 1, 600-600, Japanese, 1342-8349, 110009835725, AA11439205 - 27aCA-5 Pressure and magnetic field effect on the mixed bulk-filament superconductivity in ZrTe_3
Tsuchiya S; Yamaya K; Takayanagi S; Tanda S; Matsubayashi K; Uwatoko Y
The Physical Society of Japan (JPS), 05 Mar. 2014, Meeting abstracts of the Physical Society of Japan, 69, 1, Japanese, 1342-8349, 110009836391 - 8aPS-42 PCS studies of metamagnetic transition in Ce compounds
Motoyama G.; Ogawa S.; Miyoshi K.; Nishigori S.; Fujiwara K.; Matsubayashi K.; Yamaguchi A.; Sumiyama A.; Uwatoko Y.
The Physical Society of Japan, 2014, Meeting Abstracts of the Physical Society of Japan, 69, 0, 366-366, Japanese, 1342-8349, 110009887524, AA11439205 - CePt(Si,Ge)2の圧力効果
大屋七海; 小貫真太郎; 加瀬直樹; 中野智仁; 武田直也; 松林和幸; 上床美也
2014, 日本物理学会講演概要集, 69, 2, 1342-8349, 201402265584657850 - 重い電子系β-YbAlB4におけるAlサイトのFe置換効果と量子臨界性
冨田崇弘; 久我健太郎; 松本洋介; 中辻知; 松林和幸; 上床美也
2014, 日本物理学会講演概要集, 69, 1, 1342-8349, 201402204910999580 - 8aPS-54 Pressure effect of CePt(Si, Ge)_2
Ohya N; Onuki S; Kase N; Nakano T; Takeda N; Matsubayashi K; Ueatoko Y
一般社団法人日本物理学会, 2014, Meeting Abstracts of the Physical Society of Japan, 69, 0, Japanese, 1342-8349, 110009887535 - 28aPS-12 Development of Quantum Oscillations Measurements under Pulsed Magnetic Fields and Pressures II
Miyake A.; Uwatoko Y.; Matsuo A.; Kindo K.; Tokunaga M.; Kohama Y.; Ohta S.; Hirose Y.; Honda F.; Aoki D.; Onuki Y.; Settai R.; Matsubayashi K.
The Physical Society of Japan, 2014, Meeting Abstracts of the Physical Society of Japan, 69, 0, 596-596, Japanese, 110009835707 - Partially disordered state of triangular lattice antiferromagnet NaCo(Acac)_3 benzene
Karaki Y.; Kuga K.; Kimura K.; Matsubayashi K.; Uwatoko Y.
The Physical Society of Japan (JPS), 26 Aug. 2013, Meeting abstracts of the Physical Society of Japan, 68, 2, 361-361, Japanese, 1342-8349, 110009756534, AA11439205 - Physical properties of the Au-Al-Yb quasicrystal and approximant,and the Au-Al-Sm approximant
Matsukawa S.; Tanaka K.; Nakayama M.; Kunikata S.; Deguchi K.; lmura K.; Matsubayashi K.; Uwatoko Y.; Ishimasa T.; Sato N.K.
The Physical Society of Japan (JPS), 26 Aug. 2013, Meeting abstracts of the Physical Society of Japan, 68, 2, 462-462, Japanese, 1342-8349, 110009756924, AA11439205 - Pressure-dependent Pr valence state in PrTi_2Al_<20> probed by X-ray absorption spectroscopy
Kawamura N.; Matsubayashi K.; Ishimatsu N.; Mizumaki M.; Sakai A.; Nakatsuji S.; Uwatoko Y.; Watanabe S.
The Physical Society of Japan (JPS), 26 Aug. 2013, Meeting abstracts of the Physical Society of Japan, 68, 2, 492-492, Japanese, 1342-8349, 110009757032, AA11439205 - Pressure effect on double valence ordering transitions of EuPtp
Mitsuda A.; Umeda M.; Manabe S.; Matsubayashi K.; Mizumaki M.; Kawamura N.; Ishimatsu N.; Uwatoko Y.; Watanabe S.; Wada H.
The Physical Society of Japan (JPS), 26 Aug. 2013, Meeting abstracts of the Physical Society of Japan, 68, 2, 497-497, Japanese, 1342-8349, 110009757052, AA11439205 - High-Quality Single Crystal Growth and Electronic States of EuCd_<11>
Onuki Y.; Nakamura A.; Hiranaka Y.; Uejyo A.; Takeuchi T.; Honda F.; Matsubayashi K.; Uwatoko Y.; Hedo M.; Nakama T.; Harima H.
The Physical Society of Japan (JPS), 26 Aug. 2013, Meeting abstracts of the Physical Society of Japan, 68, 2, 497-497, Japanese, 1342-8349, 110009757054, AA11439205 - Effect of pressure on metamagnetism in YbCo_2Zn_<20> and YbNi_3Ga_9
Matsubayashi K.; Kawae T.; Yamashita T.; Ohara S.; Kitagawa K.; Uwatoko Y.
The Physical Society of Japan (JPS), 26 Aug. 2013, Meeting abstracts of the Physical Society of Japan, 68, 2, 542-542, Japanese, 1342-8349, 110009757231, AA11439205 - Pressure dependence of the electric transport properties in the valence fluctuated systems YbAlB_4
Shimura Y.; Tomita T.; Matsubayashi K.; Uwatoko Y.; Nakatsuji S.
The Physical Society of Japan (JPS), 26 Aug. 2013, Meeting abstracts of the Physical Society of Japan, 68, 2, 540-540, Japanese, 1342-8349, 110009757223, AA11439205 - 4f electronic state in YbCo_2Zn_<20> at low temperatures
Mito T.; Hara H.; Koyama T.; Ueda K.; Kohara T.; Ishida K.; Matsubayashi K.; Saiga Y.; Uwatoko Y.
The Physical Society of Japan (JPS), 26 Aug. 2013, Meeting abstracts of the Physical Society of Japan, 68, 2, 542-542, Japanese, 1342-8349, 110009757230, AA11439205 - Dynamics of magnetic monopoles in two-dimensional kagome ice state of Dy_2Ti_2O_7
Goto K.; Takatsu H.; Otsuka H.; Higashinaka R.; Kadowaki H.; Lynn J. W.; Sato T. J.; Matsuhira K.; Hiroi Z.; Matsubayashi K.; Uwatoko Y.
The Physical Society of Japan (JPS), 26 Aug. 2013, Meeting abstracts of the Physical Society of Japan, 68, 2, 391-391, Japanese, 1342-8349, 110009756654, AA11439205 - Magnetic transitions of Ho_<1-x>Gd_xRh_2Si_2(Gd=0.1)
Morita T.; Fujiwara T.; Matsubayashi K.; Uwatoko Y.; Shigeoka T.
The Physical Society of Japan (JPS), 26 Aug. 2013, Meeting abstracts of the Physical Society of Japan, 68, 2, 381-381, Japanese, 1342-8349, 110009756615, AA11439205 - Magnetic transitions of DyPd_2Ge_2 Single Crystal
Tabata K.; Fujiwara T.; Matsubayashi K.; Uwatoko Y.; Shigeoka T.
The Physical Society of Japan (JPS), 26 Aug. 2013, Meeting abstracts of the Physical Society of Japan, 68, 2, 381-381, Japanese, 1342-8349, 110009756616, AA11439205 - Magnetic property of polymorphic DyIr_2Si_2 single crystal compounds
Kurata Y.; Fujiwara T.; Matsubayashi K.; Uwatoko Y.; Shigeoka T.
The Physical Society of Japan (JPS), 26 Aug. 2013, Meeting abstracts of the Physical Society of Japan, 68, 2, 382-382, Japanese, 1342-8349, 110009756617, AA11439205 - Magnetic transitions of Ho_<1-x>Y_xRh_2Si_2(x=0.05)
Hujii Y.; Fujiwara T.; Matsubayashi K.; Uwatoko Y.; Shigeoka T.
The Physical Society of Japan (JPS), 26 Aug. 2013, Meeting abstracts of the Physical Society of Japan, 68, 2, 381-381, Japanese, 1342-8349, 110009756614, AA11439205 - Pressure Effect of Antiferromagnetic Compound Ce_2NiGa_<12>
SASAKI R.; MATSUBAYASHI K.; UWATOKO Y.; SHIRAISHI T.; YAMASHITA T.; OHARA S.
16 May 2013, 希土類 = Rare earths, 62, 136-137, Japanese, 0910-2205, 10031176349, AN10379697 - 27aPS-70 Pressure effect of the guadrupolar order in PrTi_2Al_<20>
Tanaka T.; Matsubayashi K.; Suzuki J.; Uwatoko Y.; Sakai A.; Nakatsuji S.; Hisada A.; Kitagawa K.; Kubo Y.
The Physical Society of Japan (JPS), 26 Mar. 2013, Meeting abstracts of the Physical Society of Japan, 68, 1, 626-626, Japanese, 1342-8349, 110009644688, AA11439205 - 27aPS-30 Pressure effects on the magnetic ordering phase of heavy-fermion antiferromagnetic Ce_2MGa_<12> (M=Ni,Pd,Pt)
Sasaki R.; Matsubayashi K.; Shiraishi T.; Yamashita T.; Ohara S.; Uwatoko Y.
The Physical Society of Japan (JPS), 26 Mar. 2013, Meeting abstracts of the Physical Society of Japan, 68, 1, 616-616, Japanese, 1342-8349, 110009644650, AA11439205 - 27aPS-36 Temperature-Pressure Phase Diagram of Yb Valence in YbNi_3Ga_9 Probed by X-ray Absorption and Emission Spectroscopy II
Kawamura N.; Matsubayashi K.; Kanai N.; Hayashi H.; Ishimatsu N.; Mizumaki M.; Yamashita T.; Ohara S.; Uwatoko Y.
The Physical Society of Japan (JPS), 26 Mar. 2013, Meeting abstracts of the Physical Society of Japan, 68, 1, 618-618, Japanese, 1342-8349, 110009644655, AA11439205 - 27aPS-64 Pressure effect of T_
on filled skutterudite superconductors LaT_4P_<12> (T=Fe,Ru)
Kawaai T.; Kawamura Y.; Hayashi J.; Sekine C.; Matubayashi K.; Uwatoko Y.
The Physical Society of Japan (JPS), 26 Mar. 2013, Meeting abstracts of the Physical Society of Japan, 68, 1, 624-624, Japanese, 1342-8349, 110009644682, AA11439205 - 26aXG-10 Superconducting gap anisotropy on iron-pnictides LiFeAs: laser-ARPES
Yamamoto H. Q.; Okazaki K.; Ota Y.; Kotani Y.; Kitagawa K.; Matsubayashi K.; Uwatoko Y.; Takigawa M.; Chen Chuangtian; Watanabe S.; Shin S.
The Physical Society of Japan (JPS), 26 Mar. 2013, Meeting abstracts of the Physical Society of Japan, 68, 1, 575-575, Japanese, 1342-8349, 110009644495, AA11439205 - 27aPS-142 Microwave Surface Impedance Measurement of Na(Fe,Co)As Single Crystals
Imai Y.; Koshida S.; Okada T.; Takahashi H.; Kitagawa K.; Matsubayashi K.; Uwatoko Y.; Takigawa M.; Maeda A.
The Physical Society of Japan (JPS), 26 Mar. 2013, Meeting abstracts of the Physical Society of Japan, 68, 1, 643-643, Japanese, 1342-8349, 110009644756, AA11439205 - 26pXT-2 Pressure effect of quadrupolar ordering and superconductivity on PrTi_2Al_<20>
Suzuki J.; Tanaka T.; Matsubayashi K.; Sakai A.; Nakatsuji S.; Kubo Y.; Kitagawa K.; Uwatoko Y.
The Physical Society of Japan (JPS), 26 Mar. 2013, Meeting abstracts of the Physical Society of Japan, 68, 1, 583-583, Japanese, 1342-8349, 110009644520, AA11439205 - 26aPS-36 Magnetic and conduction characteristic of Mn_<2-x>Cu_xSb
Matsubayashi K.; Uwatoko Y.
The Physical Society of Japan (JPS), 26 Mar. 2013, Meeting abstracts of the Physical Society of Japan, 68, 1, 506-506, Japanese, 1342-8349, 110009644254, AA11439205 - 26aPS-35 Magnetic Relaxation of Mn_<2-x>Co_xSb under Pressure
Orihashi Hiroki; Matsubayashi Kazuyuki; Uwatoko Yoshiya; Koyama Keiichi
The Physical Society of Japan (JPS), 26 Mar. 2013, Meeting abstracts of the Physical Society of Japan, 68, 1, 506-506, Japanese, 1342-8349, 110009644253, AA11439205 - 28pXA-9 Quantum Critical Phenomena and Pressure phase diagram in β-YbAlB_4
Tomita T.; Ebata M.; Takaahshi T.; Kuga K.; Matsumoto Y.; Nakatsuji S.; Matsubayashi K.; Uwatoko Y.
The Physical Society of Japan (JPS), 26 Mar. 2013, Meeting abstracts of the Physical Society of Japan, 68, 1, 670-670, Japanese, 1342-8349, 110009644842, AA11439205 - 28pXA-3 Pressure-induced ferromagnetism and valence crossover in YbNi_3Ga_9
Matsubayashi K.; Hirayama T.; Yamashita T.; Ohara S.; Kawamura N.; Mizumaki M.; Ishimatsu N.; Kitagawa K.; Uwatoko Y.; Watanabe S.
The Physical Society of Japan (JPS), 26 Mar. 2013, Meeting abstracts of the Physical Society of Japan, 68, 1, 669-669, Japanese, 1342-8349, 110009644836, AA11439205 - Mn2-XCuxSbの強磁場下における磁気特性及び電気的特性
松本佳大; 折橋広樹; 廣井政彦; 小山佳一; 松林和幸; 上床美也
2013, 日本金属学会講演概要(CD-ROM), 153rd, 2433-3093, 201302212375394725 - Point-contact spectra of heavy fermion compound CeRu_2Si_2 in magnetic fields
Motoyarna G.; Tachikake Y.; Matsubayshi K.; Yamaguchi A.; Sumiyama A.; Uwatoko Y.
The Physical Society of Japan, 2013, Meeting Abstracts of the Physical Society of Japan, 68, 0, 459-459, Japanese, 1342-8349, 110009756912, AA11439205 - 27aPS-23 Point Contact Spectroscopy of heavy fermion compound CeRu_2Si_2 under magnetic field
Tachikake Y.; Motoyama G.; Yamaguchi A.; Sumiyama A.; Matsubayashi K.; Uwadoko Y.
The Physical Society of Japan, 2013, Meeting Abstracts of the Physical Society of Japan, 68, 0, 615-615, Japanese, 1342-8349, 110009644643, AA11439205 - Yb2Ni12P7の圧力効果 III
佐藤亮平; 土屋勝彦; 中野智仁; 武田直也; 大橋政司; 巨海玄道; 松林和幸; 上床美也
2013, 日本物理学会講演概要集, 68, 2, 1342-8349, 201302218528918646 - パルス強磁場・ダイヤモンドアンビルセルを用いた強磁場・高圧力下物性測定法の開発
三宅厚志; 小濱芳允; 松林和幸; 上床美也; 松尾晶; 金道浩一; 徳永将史
2013, 高圧討論会講演要旨集, 54th, 0917-6373, 201302245066313210 - β-YbAl1-xFexB4における量子臨界現象と圧力相図
冨田崇弘; 江畑政哉; 高橋博樹; 久我健太郎; 松本洋介; 中辻知; 松林和幸; 上床美也
2013, 日本物理学会講演概要集, 68, 1, 1342-8349, 201302210867281117 - Pressure effect of Yb_2Ni_<12>P_7 III
Satoh R; Tsuchiya K; Nakano T; Takeda N; Ohashi M; Oomi G; Matsubayashi K; Uwatoko Y
一般社団法人日本物理学会, 2013, Meeting Abstracts of the Physical Society of Japan, 68, 0, Japanese, 1342-8349, 110009756935 - EuGa4の輸送特性に対する圧力効果
仲村愛; 平仲裕一; 立津慶幸; 眞榮平孝裕; 辺土正人; 仲間隆男; 広瀬雄介; 石田一裕; 森晶宣; 三田村勝哉; 杉山清寛; 大貫惇睦; 本多史憲; 竹内徹也; 萩原政幸; 摂待力生; 松林和幸; 上床美也
25 Oct. 2012, 高圧討論会講演要旨集, 53rd, 199, Japanese, 0917-6373, 201302293521223121 - 18aPSA-32 Magnetism and transport properties of EuNi(Ge_<1-x>)_3 compounds
Hirakawa S.; Watanabe S.; Teruya A.; Hiranaka Y.; Nakamura A.; Takaesu Y.; Hedo M.; Nakama T.; Yagasaki K.; Uchima K.; Matsubayashi K.; Uwatoko Y.
The Physical Society of Japan (JPS), 24 Aug. 2012, Meeting abstracts of the Physical Society of Japan, 67, 2, 385-385, Japanese, 1342-8349, 110009599862, AA11439205 - 20pPSB-28 Development of 10GPa-class ultrahigh-pressure NMR and bulk measurement technique
Kitagawa K.; Matsubayashi K.; Gotou H.; Matsumoto T.; Uwatoko Y.; Yagi T.; Takigawa M.
The Physical Society of Japan (JPS), 24 Aug. 2012, Meeting abstracts of the Physical Society of Japan, 67, 2, 563-563, Japanese, 1342-8349, 110009600535, AA11439205 - 21aFH-9 Metamagnetic behavior of YbCo_2Zn_<20> under pressure
Matsubayashi K.; Yamanaka R.; Kawae T.; Uwatoko Y.
The Physical Society of Japan (JPS), 24 Aug. 2012, Meeting abstracts of the Physical Society of Japan, 67, 2, 579-579, Japanese, 1342-8349, 110009600601, AA11439205 - 20pGA-10 Microwave Surface Impedance Measurement of Na(Fe,Co)As Single Crystals under Finite Magnetic Fields
Okada T.; Takahashi H.; Imai Y.; Kitagawa K.; Matsubayashi K.; Uwatoko Y.; Takigawa M.; Maeda A.
The Physical Society of Japan (JPS), 24 Aug. 2012, Meeting abstracts of the Physical Society of Japan, 67, 2, 552-552, Japanese, 1342-8349, 110009600492, AA11439205 - 20pFH-10 Electrical resistivity measurements of Ce_2TGa_<12>(T=Ni,Pd,Pt) under pressure
Sasaki R.; Matsubayashi K.; Shiraishi T.; Yamashita T.; Ohara S.; Uwatoko Y.
The Physical Society of Japan (JPS), 24 Aug. 2012, Meeting abstracts of the Physical Society of Japan, 67, 2, 549-549, Japanese, 1342-8349, 110009600479, AA11439205 - 19pHC-2 Physical properties under high pressure in quadrupolar order PrTi_2Al_<20>(Tr=Ti, V)
Tanaka T.; Matsubayashi K.; Suzuki J.; Hisada A.; Nakatsuji S.; Sakai A.; Uwatoko Y.; Kubo Y.
The Physical Society of Japan (JPS), 24 Aug. 2012, Meeting abstracts of the Physical Society of Japan, 67, 2, 491-491, Japanese, 1342-8349, 110009600246, AA11439205 - 20aPSB-15 Temperature-Pressure Phase Diagram of Yb Valence in YbNi_3Ga_9 Probed by X-ray Absorption and Emission Spectroscopy
Kawamura N.; Matsubayashi K.; Kanai N.; Hayashi H.; Ishimatsu N.; Mizumaki M.; Yamashita T.; Ohara S.; Uwatoko Y.
The Physical Society of Japan (JPS), 24 Aug. 2012, Meeting abstracts of the Physical Society of Japan, 67, 2, 527-527, Japanese, 1342-8349, 110009600392, AA11439205 - 20aPSA-66 Low temperature properties of PrTi_2Al_<20> under pressure
Suzuki J.; Tanaka T.; Matsubayashi K.; Sakai A.; Nakatsuji S.; Uwatoko Y.
The Physical Society of Japan (JPS), 24 Aug. 2012, Meeting abstracts of the Physical Society of Japan, 67, 2, 522-522, Japanese, 1342-8349, 110009600370, AA11439205 - 25pYA-4 NMR Study in Superconductivity/Antiferromagnetism Coexisting State of P-doped SrFe_2As_2
Kitagawa K.; Matsubayashi K.; Uwatoko Y.; Takigawa M.
The Physical Society of Japan (JPS), 05 Mar. 2012, Meeting abstracts of the Physical Society of Japan, 67, 1, 633-633, Japanese, 1342-8349, 110009567150, AA11439205 - 24aPS-47 圧力下磁化測定によるMn_<2-x>Co_xSbのカイネティックアレスト効果の研究(24aPS 領域3ポスターセッション,領域3(磁性,磁気共鳴))
折橋 広樹; 小山 佳一; 松林 和幸; 上床 美也
一般社団法人日本物理学会, 05 Mar. 2012, 日本物理学会講演概要集, 67, 1, 486-486, Japanese, 1342-8349, 110009566600, AA11439205 - 26pSA-22 Sample dependence of Bi_2Te_3 and physical properties under hydrostatic pressure
Terai T.; Matsubayashi K.; Jin C. Q.; Zhou J.; Uwatoko Y.
The Physical Society of Japan (JPS), 05 Mar. 2012, Meeting abstracts of the Physical Society of Japan, 67, 1, 753-753, Japanese, 1342-8349, 110009567591, AA11439205 - 27aYB-9 Pressure induced ferromagnetically ordered state in intermediate valence system YbNi_3Ga_9
Hirayama T.; Matsubayashi K.; Yamashita T.; Ohara S.; Uwatoko Y.
The Physical Society of Japan (JPS), 05 Mar. 2012, Meeting abstracts of the Physical Society of Japan, 67, 1, 682-682, Japanese, 1342-8349, 110009567328, AA11439205 - 27aYB-6 Quantum Criticality of Heavy Fermion Compound YbCo_2Zn_<20> under Pressure and Magnetic Field
Yamanaka R.; Matsubayashi K.; Saiga Y.; Kawae T.; Uwatoko Y.
The Physical Society of Japan (JPS), 05 Mar. 2012, Meeting abstracts of the Physical Society of Japan, 67, 1, 681-681, Japanese, 1342-8349, 110009567325, AA11439205 - 25pPSB-22 Pressure Effect of Superconductivity on La series filled skutterudite
Kawamura Y.; Kawai T.; Sekine C.; Matsubayashi K.; Uwatoko Y.
The Physical Society of Japan (JPS), 05 Mar. 2012, Meeting abstracts of the Physical Society of Japan, 67, 1, 650-650, Japanese, 1342-8349, 110009567210, AA11439205 - 26pYA-4 Temperature-Pressure Phase diagram of PrTr_2Al_<20> (Tr=Ti, V)
Tanaka T.; Matsubayashi K.; Hisada A.; Nakatsuji S.; Sakai A.; Uwatoko Y.; Kubo Y.
The Physical Society of Japan (JPS), 05 Mar. 2012, Meeting abstracts of the Physical Society of Japan, 67, 1, 662-662, Japanese, 1342-8349, 110009567258, AA11439205 - 24aYA-13 Flux-flow and Electronic Structure of LiFe(As,P) Single Crystals Investigated by Microwave Surface Impedance under Finite Magnetic Fields
Okada T.; Takahashi H.; Imai Y.; Kitagawa K.; Matsubayashi K.; Takigawa M.; Uwatoko Y.; Maeda A.
The Physical Society of Japan (JPS), 05 Mar. 2012, Meeting abstracts of the Physical Society of Japan, 67, 1, 544-544, Japanese, 1342-8349, 110009566820, AA11439205 - 24pYA-6 Microwave Surface Impedance Measurements of SrFe_2(As,P)_2 Single Crystals
Takahashi H.; Imai Y.; Okada T.; Kitagawa K.; Matsubayashi K.; Uwatoko Y.; Maeda A.
The Physical Society of Japan (JPS), 05 Mar. 2012, Meeting abstracts of the Physical Society of Japan, 67, 1, 555-555, Japanese, 1342-8349, 110009566862, AA11439205 - 24pPSB-46 Magnetization and Transport properties under Pressure of Single Crystalline CeIrIn_5
Takaesu Y.; Aso N.; Tamaki Y.; Hedo M.; Nakama T.; Ishikawa Y.; Deguchi K.; Sato N. K.; Matsubayashi K.; Uwatoko Y.
The Physical Society of Japan (JPS), 05 Mar. 2012, Meeting abstracts of the Physical Society of Japan, 67, 1, 574-574, Japanese, 1342-8349, 110009566935, AA11439205 - 24pPSB-53 Electrical resistivity measurement under pressure of the heavy fermion antiferromagnetic Ce_2PtGa_<12>
Sasaki R.; Matsubayashi K.; Shiraishi T.; Yamashita T.; Ohara S.; Uwatoko Y.
The Physical Society of Japan (JPS), 05 Mar. 2012, Meeting abstracts of the Physical Society of Japan, 67, 1, 576-576, Japanese, 1342-8349, 110009566942, AA11439205 - Mn2-xCoxSbの磁気緩和
折橋広樹; 小山佳一; 松林和幸; 上床美也
2012, 日本金属学会講演概要(CD-ROM), 151st, 2433-3093, 201202222064023098 - Mn2-xCoxSbの圧力下磁化測定
折橋広樹; 小山佳一; 松林和幸; 上床美也
2012, 日本金属学会講演概要(CD-ROM), 150th, 2433-3093, 201202284858547704 - Mn2Sb1-xGex(0.05≦x≦0.2)の強磁場下磁気特性
島田大輔; 折橋広樹; 満永大輔; 伊藤昌和; 廣井政彦; 小山佳一; 小野寺礼尚; 高橋弘紀; 松林和幸; 上床美也
2012, 日本金属学会講演概要(CD-ROM), 151st, 2433-3093, 201202294356381476 - 磁場侵入長・フラックスフローからみたSrFe2(As,P)2の超伝導ギャップ構造
高橋英幸; 高橋英幸; 前田京剛; 前田京剛; 今井良宗; 今井良宗; 岡田達典; 岡田達典; 北川健太郎; 北川健太郎; 松林和幸; 松林和幸; 瀧川仁; 瀧川仁; 上床美也; 上床美也
2012, 応用物理学関係連合講演会講演予稿集(CD-ROM), 59th, 201202234509643162 - LiFe(As,P)単結晶の磁場中マイクロ波表面インピーダンス測定
岡田達典; 岡田達典; 高橋英幸; 高橋英幸; 今井良宗; 今井良宗; 北川健太郎; 北川健太郎; 松林和幸; 松林和幸; 上床美也; 上床美也; 前田京剛; 前田京剛
2012, 応用物理学関係連合講演会講演予稿集(CD-ROM), 59th, 201202276875289201 - Magnetic properties of Mn2-xCoxSb (x=0.17,0.2) under high magnetic fields
折橋広樹; 満永大輔; 廣井政彦; 三井好古; 高橋弘紀; 渡辺和雄; 松林和幸; 上床美也; 小山佳一
2012, 鹿児島大学理学部紀要(Web), 45, 201302238271315814 - CePtSi2単結晶の圧力効果 II
中野智仁; 小貫真太郎; 佐藤亮平; 笹原拓也; 武田直也; 松林和幸; 上床美也
2012, 日本物理学会講演概要集, 67, 1, 1342-8349, 201202296913915635 - 重い電子系Yb化合物β-YbAlB4の圧力誘起量子臨界現象
冨田崇弘; 高橋博樹; 江畑政哉; 久我健太郎; 中辻知; 松林和幸; 上床美也
2012, 高圧討論会講演要旨集, 53rd, 0917-6373, 201302257601825703 - 25aYB-10 Pressure effect of CePtSi_2 single crystal II
Nakano T; Onuki S; Satoh R; Sasahara T; Takeda N; Matsubayashi K; Uwatoko Y
一般社団法人日本物理学会, 2012, Meeting Abstracts of the Physical Society of Japan, 67, 0, Japanese, 1342-8349, 110009566986 - 24aBK-5 High-pressure study on novel single-component κ-type organic conductors bridged by hydrogen bond
Isono T; Murakami Y; Uruichi M; Yamamoto K; Matsubayashi K; Uwatoko Y; Mori H; Kamo H; Shikama T; Ueda A; Takahashi K; Nakao A; Kumai R; Kobayashi K; Nakao H
The Physical Society of Japan, 2012, Meeting Abstracts of the Physical Society of Japan, 67, 0, Japanese, 110009567998 - 22pGM-16 NMR study of P-doped SrFe_2As_2 : Superconductivity induced by chemical pressure
Kitagawa K.; Matsubayashi K.; Uwatoko Y.; Takigawa M.
The Physical Society of Japan (JPS), 24 Aug. 2011, Meeting abstracts of the Physical Society of Japan, 66, 2, 551-551, Japanese, 1342-8349, 110008759267, AA11439205 - 24pGH-5 Microwave Surface Impedance Measurements of LiFeAs Single Crystal under Finite Magnetic Fields
Okada T.; Takahashi H.; Imai Y.; Kitagawa K.; Matsubayashi K.; Takigawa M.; Uwatoko Y.; Maeda A.
The Physical Society of Japan (JPS), 24 Aug. 2011, Meeting abstracts of the Physical Society of Japan, 66, 2, 656-656, Japanese, 1342-8349, 110008759648, AA11439205 - 24pGC-6 Pressure dependence of Quadrupolar Order in PrTr_2Al_<20>(Tr=Ti,V)
Tanaka T.; Matsubayashi K.; Uwatoko Y.; Sakai A.; Nakatsuji S.; Kubo Y.
The Physical Society of Japan (JPS), 24 Aug. 2011, Meeting abstracts of the Physical Society of Japan, 66, 2, 649-649, Japanese, 1342-8349, 110008759621, AA11439205 - 23pGC-4 Pressure effects on heavy-fermion antiferromagnet Ce_2MGa_<12>(M=Ni,Pd,Pt)
Ohara S.; Shiraishi T.; Yamashita T.; Matsubayashi K.; Uwatoko Y.
The Physical Society of Japan (JPS), 24 Aug. 2011, Meeting abstracts of the Physical Society of Japan, 66, 2, 610-610, Japanese, 1342-8349, 110008759486, AA11439205 - 23aPS-60 Pressure dependence of Magnetic Properties and Electric resistance in YbNi_3Al_9
Hirayama T.; Tanaka T.; Munakata K.; Matsubayashi K.; Yamashita T.; Ohara S.; Ohara Y.; Uwatoko Y.
The Physical Society of Japan (JPS), 24 Aug. 2011, Meeting abstracts of the Physical Society of Japan, 66, 2, 591-591, Japanese, 1342-8349, 110008759410, AA11439205 - 23pGM-7 Relation between the Quasiparticle Scattering and the Superfluid Densities in "11" FeSe_<1-x>Te_x and "111" LiFeAs
Takahashi H.; Imai Y.; Okada T.; Komiya S.; Kitagawa K.; Matsubayashi K.; Tsukada I.; Takigawa M.; Uwatoko Y.; Maeda A.
The Physical Society of Japan (JPS), 24 Aug. 2011, Meeting abstracts of the Physical Society of Japan, 66, 2, 625-625, Japanese, 1342-8349, 110008759531, AA11439205 - 鉄系超伝導体Fe(Se1−xSx)(0.1≦x≦0.3)の圧力温度相図
冨田崇弘; 冨田崇弘; 高橋弘幸; 高橋博樹; 高橋博樹; 水口佳一; 水口佳一; 高野義彦; 高野義彦; 高野義彦; 松林和幸; 上床美也
24 Aug. 2011, 日本物理学会講演概要集, 66, 2, 626, Japanese, 1342-8349, 201102217452454520 - LiFeAsの渦糸芯状態と超伝導ギャップ
花栗哲郎; 北川健太郎; 松林和幸; 目崎雄二; 上床美也; 瀧川仁; 高木英典
24 Aug. 2011, 日本物理学会講演概要集, 66, 2, 488, Japanese, 1342-8349, 201102262893699621 - High Pressure Effect of PrTr_2Al_<20>(Tr=Ti,V,Cr)
TANAKA T.; SAKAI A.; MATSUBAYASHI K.; NAKATSUJI S.; UWATOKO Y.; KUBO Y.
05 May 2011, 希土類 = Rare earths, 58, 196-197, Japanese, 0910-2205, 10028249726, AN10379697 - 28pED-1 Microwave Surface Impedance Measurements of LiFe(As,P) Single Crystal under Finite Magnetic Fields
Okada T.; Takahashi H.; Imai Y.; Kitagawa K.; Matsubayashi K.; Takigawa M.; Uwatoko Y.; Maeda A.
The Physical Society of Japan (JPS), 03 Mar. 2011, Meeting abstracts of the Physical Society of Japan, 66, 1, 679-679, Japanese, 1342-8349, 110008714700, AA11439205 - 26pEJ-5 Ultrahigh-pressure NMR study on NaFeAs single crystals
Kitagawa K.; Mezaki Y.; Matsubayashi K.; Uwatoko Y.; Takigawa M.
The Physical Society of Japan (JPS), 03 Mar. 2011, Meeting abstracts of the Physical Society of Japan, 66, 1, 612-612, Japanese, 1342-8349, 110008714463, AA11439205 - 25aPS-98 Electronic structure and Effect of Pressure in PrT_2Al_<20>
Tanaka T.; Sakai A.; Matsubayashi K.; Nakatsuji S.; Uwatoko Y.; Kubo Y.
The Physical Society of Japan (JPS), 03 Mar. 2011, Meeting abstracts of the Physical Society of Japan, 66, 1, 536-536, Japanese, 1342-8349, 110008714175, AA11439205 - 26aEC-9 Pressure effect on YbNi_3X_9(X=Al,Ga) single crystal
Hirayama T.; Matsubayashi K.; Yamashita T.; Ohara S.; Munakata K.; Uwatoko Y.
The Physical Society of Japan (JPS), 03 Mar. 2011, Meeting abstracts of the Physical Society of Japan, 66, 1, 583-583, Japanese, 1342-8349, 110008714358, AA11439205 - 27pGW-3 Pressure Effect on Fe-based Superconductors FeSe_<1-x>S_x
Tomita T; Takahashi H; Takahashi H; Mizuguchi Y; Takano Y; Matsubayashi K; Uwatoko Y
The Physical Society of Japan (JPS), 03 Mar. 2011, Meeting abstracts of the Physical Society of Japan, 66, 1, Japanese, 1342-8349, 110008714560 - Fe(Se1−xSx)(x=0.1,0.2,0.3)の圧力効果
冨田崇弘; 冨田崇弘; 高橋弘幸; 高橋博樹; 高橋博樹; 水口佳一; 水口佳一; 高野義彦; 高野義彦; 高野義彦; 松林和幸; 上床美也
03 Mar. 2011, 日本物理学会講演概要集, 66, 1, 641, Japanese, 1342-8349, 201102294639519833 - 26pEJ-3 Microwave Surface Impedance Measurements of LiFe(As,P) Single Crystals
Imai Y; Takahashi H; Okada T; Kitagawa K; Matsubayashi K; Nakai N; Nagai Y; Takigawa M; Uwatoko Y; Machida M; Maeda A
The Physical Society of Japan (JPS), 03 Mar. 2011, Meeting abstracts of the Physical Society of Japan, 66, 1, Japanese, 1342-8349, 110008714461 - 26pEJ-4 A Comparative Study on Microwave Complex Conductivity of LiFeAs and FeSe_<1-x>Te_x Single Crystals
Takahashi H; Imai Y; Okada T; Komiya S; Kitagawa K; Matsubayashi K; Nakai N; Nagai Y; Tsukada I; Takigawa M; Uwatoko Y; Machida M; Maeda A
The Physical Society of Japan (JPS), 03 Mar. 2011, Meeting abstracts of the Physical Society of Japan, 66, 1, Japanese, 1342-8349, 110008714462 - 25aTA-8 Conducting and magnetic properties for β-(meso-DMBEDT-TTF)_2PF_6
Shikama T.; Krivickas Sara; Takahashi K.; Mori H.; Matsubayashi K.; Uwatoko Y.; Kimata M.; Tajima H.; Yoshizawa H.
The Physical Society of Japan, 2011, Meeting Abstracts of the Physical Society of Japan, 66, 0, 843-843, Japanese, 1342-8349, 110008715289, AA11439205 - 21pGL-11 Vortex-core state and superconducting gap in LiFeAs
Hanaguri T.; Kitagawa K.; Matsubayashi K.; Mezaki Y.; Uwatoko Y.; Takigawa M.; Takagi H.
The Physical Society of Japan, 2011, Meeting Abstracts of the Physical Society of Japan, 66, 0, 488-488, Japanese, 1342-8349, 110008759038, AA11439205 - 鉄系超伝導体における準粒子散乱と超流体密度の温度依存性の関係
前田京剛; 前田京剛; 高橋英幸; 高橋英幸; 今井良宗; 今井良宗; 小宮世紀; 小宮世紀; 北川健太郎; 北川健太郎; 松林和幸; 松林和幸; 塚田一郎; 塚田一郎; 上床美也; 上床美也; 瀧川仁; 瀧川仁
2011, 応用物理学会学術講演会講演予稿集(CD-ROM), 72nd, 201102255708291844 - LiFeAsとFeSe1-xTex単結晶のマイクロ波複素電気伝導度の比較
高橋英幸; 高橋英幸; 今井良宗; 今井良宗; 岡田達典; 岡田達典; 小宮世紀; 小宮世紀; 北川健太郎; 北川健太郎; 松林和幸; 松林和幸; 中井宣之; 中井宣之; 永井佑紀; 永井佑紀; 永井佑紀; 塚田一郎; 塚田一郎; 瀧川仁; 瀧川仁; 上床美也; 上床美也; 町田昌彦; 町田昌彦; 町田昌彦; 前田京剛; 前田京剛
2011, 日本物理学会講演概要集, 66, 1, 1342-8349, 201102218991692229 - 23aPS-48 Pressure-induced phase transition of the heavy fermion system β-YbAl_<1-x>Fe_xB_4
Shirasaki N.; Tomita T.; Takahashi H.; Kuga K; Nakatsuji S.; Matsubayashi K.; Uwatoko Y.
The Physical Society of Japan, 2011, Meeting Abstracts of the Physical Society of Japan, 66, 0, 588-588, Japanese, 2189-0803, 110008759398 - Development of Cubic Anvil Type High Pressure Apparatus for Neutron Scattering at Low Temperature
Koji Munakata; Hideki Ishida; Kittiwit Mathan; Soushi Ibuka; Taku J. Sato; Masakazu Nishi; Kazuyuki Matsubayashi; Yoshiya Uwatoko; Hiroyuki Kagi
INT UNION CRYSTALLOGRAPHY, 2011, ACTA CRYSTALLOGRAPHICA A-FOUNDATION AND ADVANCES, 67, C814-C815, English, Summary international conference, 2053-2733, WOS:000484219404027 - CeRu2Al10のRuサイト置換効果
小林理気; 平井大士; 川村幸裕; 西岡孝; 加藤治一; 松村政博; 小玉一人; 谷田博司; 世良正文; 松林和幸; 上床美也
2011, 日本物理学会講演概要集, 66, 1, 1342-8349, 201102230990986474 - 重い電子系β-YbAl1-xFexB4の圧力誘起相転移
白崎暢大; 冨田崇弘; 冨田崇弘; 高橋博樹; 高橋博樹; 久我健太郎; 中辻知; 松林和幸; 上床美也
2011, 日本物理学会講演概要集, 66, 2, 1342-8349, 201102299240347186 - High Pressure Phase Diagrams of AFeAs (A=Li, Na) under Highly Hydrostatic Conditions
MATSUBAYASHI Kazuyuki; KITAGAWA Kentaro; TAKIGAWA Masashi; UWATOKO Yoshiya; MEZAKI Yuji
11 Oct. 2010, 高圧討論会講演集, 51, 205-205, Japanese, 0917-6373, 10026724065, AA11948559 - Pressure effect on iron-based superconductor Fe(Se_<0.8>S_<0.2>)
TAKAHASHI Hiroyuki; TOMITA Takahiro; TAKAHASHI Hiroki; OKADA Hironari; MIZUGUCHI Yoshikazu; TAKANO Yoshihiko; MATSUBAYASHI Kazuyuki; UWATOKO Yoshiya
11 Oct. 2010, 高圧討論会講演集, 51, 0, Japanese, 0917-6373, 10026724060 - 鉄系超伝導体Fe(Se0.8S0.2)の圧力効果
高橋弘幸; 冨田崇弘; 冨田崇弘; 高橋博樹; 高橋博樹; 岡田宏成; 水口佳一; 水口佳一; 水口佳一; 高野義彦; 高野義彦; 高野義彦; 松林和幸; 松林和幸; 上床美也; 上床美也
11 Oct. 2010, 高圧討論会講演要旨集, 51st, 204, Japanese, 0917-6373, 201002263906251357 - 23pPSB-5 Superconducting properties of RPt_4Ge_<12> (R=La,Pr,Nd) under high pressure
Kondo Naoya; Umehara Izuru; Yamanaka Rina; Uwatoko Yoshiya; Matsumura Kazuyuki
The Physical Society of Japan (JPS), 18 Aug. 2010, Meeting abstracts of the Physical Society of Japan, 65, 2, 528-528, Japanese, 1342-8349, 110008098454, AA11439205 - 23aWG-11 Magnetic and transport properties of Kondo lattice antiferromagnet YbNi_3Al_9
Ohara S.; Yamashita T.; Miyazaki R.; Aoki Y.; Munakata K.; Matsubayashi K.; Uwatoko Y.; Tanaka T.; Kubo Y.; Sakamoto I.
The Physical Society of Japan (JPS), 18 Aug. 2010, Meeting abstracts of the Physical Society of Japan, 65, 2, 451-451, Japanese, 1342-8349, 110008098151, AA11439205 - 23pPSA-36 Electronic structure and High Pressure effect of PrTi_2Al_<20>
Tanaka T.; Sakai A.; Matsubayashi K.; Hisada A.; Nakatsuji S.; Uwatoko Y.; Kubo Y.
The Physical Society of Japan (JPS), 18 Aug. 2010, Meeting abstracts of the Physical Society of Japan, 65, 2, 519-519, Japanese, 1342-8349, 110008098417, AA11439205 - 24pWH-9 Ultrahigh-pressure NMR study on NaFeAs single crystals
Kitagawa K.; Mezaki Y.; Matsubayashi K.; Uwatoko Y.; Takigawa M.
The Physical Society of Japan (JPS), 18 Aug. 2010, Meeting abstracts of the Physical Society of Japan, 65, 2, 571-571, Japanese, 1342-8349, 110008098614, AA11439205 - 25aWH-1 Pressure-induced superconductivity on NaFeAs single crystal
Matsubayashi K.; Mezaki Y.; Kitagawa K.; Munakata K.; Takigawa M.; Uwatoko Y.
The Physical Society of Japan (JPS), 18 Aug. 2010, Meeting abstracts of the Physical Society of Japan, 65, 2, 581-581, Japanese, 1342-8349, 110008098654, AA11439205 - 23aPS-68 Fabrication of single crystals of 111-type iron-based superconductor and related materials
Mezaki Y.; Kitagawa K.; Matsubayashi K.; Uwatoko Y.; Takigawa M.; Takano Y.
The Physical Society of Japan (JPS), 18 Aug. 2010, Meeting abstracts of the Physical Society of Japan, 65, 2, 475-475, Japanese, 1342-8349, 110008098250, AA11439205 - 23aPS-72 The Properties of FeSe in high pressure
Yamada M; Miwa K; Umehara I; Uwatoko Y; matsubayashi K; Takano T; Mizuguchi K; Cao Shixun
The Physical Society of Japan (JPS), 18 Aug. 2010, Meeting abstracts of the Physical Society of Japan, 65, 2, Japanese, 1342-8349, 110008098254 - 23aPS-73 Measurement of physical properties of FeSeTe under pressure
Miwa K; Yamada M; Umehara I; Uwatoko Y; Matsubayashi K; Takano Y; Mizuguchi K; Cao Shixun
The Physical Society of Japan (JPS), 18 Aug. 2010, Meeting abstracts of the Physical Society of Japan, 65, 2, Japanese, 1342-8349, 110008098255 - 23aPS-74 Pressure effect on iron-based superconductor Fe(Se_<0.8>S_<0.2>)
Takahashi H; Tomita T; Takahashi H; Okada H; Mizuguchi Y; Takano Y; Matsubayashi K; Uwatoko Y
The Physical Society of Japan (JPS), 18 Aug. 2010, Meeting abstracts of the Physical Society of Japan, 65, 2, Japanese, 1342-8349, 110008098256 - Fe(Se0.8S0.2)の圧力効果
高橋弘幸; 冨田祟弘; 冨田祟弘; 高橋博樹; 高橋博樹; 岡田宏成; 水口佳一; 水口佳一; 水口佳一; 高野義彦; 高野義彦; 高野義彦; 松林和幸; 上床美也
18 Aug. 2010, 日本物理学会講演概要集, 65, 2, 477, Japanese, 1342-8349, 201002236855494970 - FeSeTeの圧力下物性測定
三輪圭史; 山田美穂; 梅原出; 上床美也; 松林和幸; 高野義彦; 水口佳一; CAO Shixun
18 Aug. 2010, 日本物理学会講演概要集, 65, 2, 477, Japanese, 1342-8349, 201002280362039296 - FeSeの高圧下での物性測定
山田美穂; 三輪啓史; 梅原出; 上床美也; 松林和幸; 高野義彦; 水口佳一; CAO Shixun
18 Aug. 2010, 日本物理学会講演概要集, 65, 2, 476, Japanese, 1342-8349, 201002282036845439 - CeAl2の高圧力下比熱測定
吉田達哉; 梅原出; 巨海玄道; 中野智仁; 大橋政司; 上床美也; 松林和幸; 辺土正人
18 Aug. 2010, 日本物理学会講演概要集, 65, 2, 538, Japanese, 1342-8349, 201002251717897132 - 反強磁性体Ce2MgSi2の圧力効果 2
本多史憲; 吉谷尚久; 広瀬雄介; 竹内徹也; 松林和幸; 上床美也; 摂待力生; 大貫惇睦
18 Aug. 2010, 日本物理学会講演概要集, 65, 2, 537, Japanese, 1342-8349, 201002298554035835 - 25aWH-9 Microwave Surface Impedance Measurements of LiFeAs Single Crystals
Imai Y; Takahashi H; Kitagawa K; Matsubayashi K; Nakai N; Nagai Y; Takigawa M; Uwatoko Y; Maeda A
The Physical Society of Japan (JPS), 18 Aug. 2010, Meeting abstracts of the Physical Society of Japan, 65, 2, Japanese, 1342-8349, 110008098661 - LiFeAsのSTM/STS
花栗哲郎; 北川健太郎; 松林和幸; 目崎雄二; 上床美也; 瀧川仁; 高木英典
18 Aug. 2010, 日本物理学会講演概要集, 65, 2, 617, Japanese, 1342-8349, 201002287362629500 - XAS and XMCD measurements for iron-based superconductor EuFe_2As_2 under high pressure
MUNAKATA K.; KAWAMURA N.; MATSUBAYASHI K.; MIZUMAKI M.; ISHIMATSU N.; ISOBE M.; KATAYAMA N.; OHGUSHI K.; UEDA Y.; UWATOKO Y.
20 May 2010, 希土類 = Rare earths, 56, 92-93, Japanese, 0910-2205, 10026391228, AN10379697 - Effect of pressure on the physical properties of Ce_2Ni_5C_3
YAMADA A.; KONDO K.; KOSAKA M.; KATANO S.; MATSUBAYASHI K.; UWATOKO Y.
20 May 2010, 希土類 = Rare earths, 56, 94-95, Japanese, 0910-2205, 10026391233, AN10379697 - 20pGD-5 Cryatalline-Electric-Field Effect and Physical Properties under High Pressure on Rare-earth Tri-telluride TbTe_3
Iwase H.; Deguchi K.; Matsubayashi K.; Munakata K.; Uwatoko Y.; Sato N. K.
The Physical Society of Japan (JPS), 01 Mar. 2010, Meeting abstracts of the Physical Society of Japan, 65, 1, 553-553, Japanese, 1342-8349, 110007655845, AA11439205 - 22pGH-7 As, Li-NMR study of LiFeAs using clean single crystals
Kitagawa K.; Matsubayashi K.; Mezaki Y.; Uwatoko Y.; Takigawa M.
The Physical Society of Japan (JPS), 01 Mar. 2010, Meeting abstracts of the Physical Society of Japan, 65, 1, 660-660, Japanese, 1342-8349, 110007656231, AA11439205 - CeRhGe2の圧力誘起超伝導
広瀬雄介; 本多史憲; 中村太一; 吉谷尚久; 山本悦嗣; 芳賀芳範; 竹内徹也; 廣田和馬; 松浦直人; 上床美也; 松林和幸; 萩原政幸; 金道浩一; 杉山清寛; 摂待力生; 大貫惇睦
01 Mar. 2010, 日本物理学会講演概要集, 65, 1, 657, Japanese, 1342-8349, 201002246226499743 - 反強磁性体Ce2MgSi2の圧力効果
本多史憲; 吉谷尚久; 広瀬雄介; 西村尚人; 吉内伸吾; 竹内徹也; 松林和幸; 上床美也; 杉山清寛; 摂待力生; 大貫惇睦
01 Mar. 2010, 日本物理学会講演概要集, 65, 1, 552, Japanese, 1342-8349, 201002294158073842 - 新超伝導体HgxReO3の高圧合成
大串研也; 山本文子; 山本文子; 木内陽子; GANGULI Chandreyee; 松林和幸; 上床美也; 高木英典; 高木英典; 高木英典
2010, 日本物理学会講演概要集, 65, 2, 1342-8349, 201002232548304971 - 新超伝導体HgxReO3の高圧合成
大串研也; 大串研也; 山本文子; 山本文子; 木内陽子; GANGULI Chandreyee; 松林和幸; 松林和幸; 上床美也; 上床美也; 高木英典; 高木英典; 高木英典
2010, 高圧討論会講演要旨集, 51st, 0917-6373, 201002212562827765 - LiFeAs,FeSe1-xTex単結晶のマイクロ波表面インピーダンス測定と超伝導ギャップ構造
今井良宗; 今井良宗; 高橋英幸; 高橋英幸; 小宮世紀; 小宮世紀; 北川健太郎; 北川健太郎; 松林和幸; 松林和幸; 塚田一郎; 塚田一郎; 瀧川仁; 瀧川仁; 上床美也; 上床美也; 前田京剛; 前田京剛
2010, 応用物理学会学術講演会講演予稿集(CD-ROM), 71st, 201002208100321745 - CeRu2Al10の置換効果
小林理気; 西岡孝; 加藤治一; 松村政博; 小玉一人; 谷田博司; 世良正文; 松林和幸; 上床美也
2010, 日本物理学会講演概要集, 65, 2, 1342-8349, 201002269466825710 - Ce0.87La0.13(Ru1-xRhx)2Si2の電気抵抗と磁性
雨海有佑; 原田英一郎; 高野英明; 桃野直樹; 村山茂幸; 中野智仁; 松林和幸; 上床美也
2010, 日本物理学会講演概要集, 65, 1, 1342-8349, 201002243412661977 - 重い電子系β-YbAlB4における低温高圧下での量子臨界性
冨田崇弘; 久我健太郎; 堀江直樹; 松本洋介; 中辻知; 松林和幸; 松本武彦; 上床美也
2010, 日本物理学会講演概要集, 65, 1, 1342-8349, 201002219297795460 - 20pGD-3 Resistivity and Magnetic Properties of Ce_<0.87>La_<0.13>(Ru_<1-x>Rh_x)_2Si_2
Amakai Y; Harada E; Takano H; Momono N; Murayama S; Nakano T; Matsubayashi K; Uwatoko Y
一般社団法人日本物理学会, 2010, Meeting Abstracts of the Physical Society of Japan, 65, 0, Japanese, 1342-8349, 110007655768 - 23pPSB-47 Measurement of Specific Heat of CeAl_2 under High Pressure
Yoshida T; Umehara I; Oomi G; Nakano T; Oohashi M; Uwatoko Y; Matsubayashi K; Hedo M
一般社団法人日本物理学会, 2010, Meeting Abstracts of the Physical Society of Japan, 65, 0, Japanese, 1342-8349, 110008098493 - Electrical resistivity and thermal expansion investigation of golden SmS under pressure
Keiichiro Imura; Kazuyuki Matsubayashi; Hiroyuki S Suzuki; Kazuhiko Deguchi; Noriaki K Sato
2010, J. Phys.: Conf. Series, 200, 012067, English, Peer-reviwed, Summary national conference - High-Pressure Ac Specific Heat Technique with Cubic Anvil Apparatus
K. Matsubayashi; M. Hedo; I. Umehara; N. Katayama; K. Ohgushi; A. Yamada; K. Munakata; T. Matsumoto; Y. Uwatoko
We report the development of ac specific heat technique under highly hydrostatic pressures using a cubic anvil apparatus. The constructed system is sensitive enough to detect a magnetic phase transition, pressure up to 8 GPa and temperature range between 2 and 30 K. We present the results of specific heat measurement of ternary iron arsenide EuFe2As2 single crystal up to 4.0 GPa with the technique presented here. © 2010 IOP Publishing Ltd., 2010, Journal of Physics: Conf. Ser., 215, 012187, English, 1742-6588, 1742-6596, 77951946502 - 26aWH-10 STM/STS studies on LiFeAs
Hanaguri T.; Kitagawa K.; Matsubayashi K.; Mazaki Y.; Uwatoko Y.; Takigawa M.; Takagi H.
The Physical Society of Japan, 2010, Meeting Abstracts of the Physical Society of Japan, 65, 0, 617-617, Japanese, 110008098784 - 25aTJ-6 Pressure effect of CePtSi_2 II
NAKANO T.; OHASHI M.; MATSUBAYASHI K.; UWATOKO Y.; OOMI G.
The Physical Society of Japan (JPS), 18 Aug. 2009, Meeting abstracts of the Physical Society of Japan, 64, 2, 414-414, Japanese, 1342-8349, 110007497490, AA11439205 - 25aTJ-12 Physical properties of Rare-earth Tri-telluride TbTe_3 Under Pressure
Iwase H.; Deguchi K.; Matsubayashi K.; Munakata K.; Uwatoko Y.; Sato N. K.
The Physical Society of Japan (JPS), 18 Aug. 2009, Meeting abstracts of the Physical Society of Japan, 64, 2, 416-416, Japanese, 1342-8349, 110007497496, AA11439205 - CeRhGe2の磁性と圧力誘起超伝導
広瀬雄介; 本多史憲; 中村太一; 吉谷尚久; 山本悦嗣; 芳賀芳範; 竹内徹也; 廣田和馬; 松浦直人; 上床美也; 松林和幸; 萩原政幸; 金道浩一; 杉山清寛; 摂待力生; 大貫惇睦
18 Aug. 2009, 日本物理学会講演概要集, 64, 2, 421, Japanese, 1342-8349, 200902254952519488 - 27pTL-6 Pressure vs Temperature phase diagram of golden SmS
Imura K.; Matsubayashi K.; Suzuki H. S.; Deguchi K.; Sato N. K.
The Physical Society of Japan (JPS), 03 Mar. 2009, Meeting abstracts of the Physical Society of Japan, 64, 1, 563-563, Japanese, 1342-8349, 110007371769, AA11439205 - 27aPS-59 Physical properties of YbM_<1-x>T_xCu_4 (M=Ag,Cd, T=In,Sn)
Yuasa F; Hiraoka K; Uwatoko Y; Matsubayashi K; Kojima K
一般社団法人日本物理学会, 03 Mar. 2009, Meeting abstracts of the Physical Society of Japan, 64, 1, Japanese, 1342-8349, 110007371702 - 27aPS-60 Quantum Phase Transition in YbXCu_4 (X=Ag,Cd,In,Au)
Utsunomiya K; Hiraoka K; Uwatoko Y; Matsubayashi K; Kojima K
一般社団法人日本物理学会, 03 Mar. 2009, Meeting abstracts of the Physical Society of Japan, 64, 1, Japanese, 1342-8349, 110007371703 - Pressure enhancement of superconductivity in an iron-based layered compound LaFeAsO(1-x)F(x)
H. Takahashi; K. Igawa; Y. Takahashi; K. Arii; H. Okada; Y. Kamihara; M. Hirano; H. Hosono; K. Matsubayashi; Y. Uwatoko; S. Nakano; T. Kikegawa
Electrical resistivity measurements under high pressure were performed on iron-based superconductor LaFeAsO(1-x)F(x). A steep increase in superconducting transition temperature (T(C)) was observed for "optimum-doped" LaFeAsO(0.89)F(0.11), whereas "under-doped" LaFeAsO(0.95)F(0.05) shows a moderate increase in T(C) with applying pressure. X-ray diffraction measurements were also performed under high pressure up to 10 GPa. A ratio c/a was observed to decrease with applying pressure, which is similar to the pressure effect on cuprate high-T(C) superconductors., IOP PUBLISHING LTD, 2009, 25TH INTERNATIONAL CONFERENCE ON LOW TEMPERATURE PHYSICS (LT25), PT 5A, 150, 5a, 052257, English, 1742-6588, WOS:000299118200026 - CePtSi2の圧力効果 II
中野智仁; 大橋政司; 大橋政司; 松林和幸; 上床美也; 巨海玄道
2009, 日本物理学会講演概要集, 64, 1, 1342-8349, 200902247229034593 - CePtSi2の圧力効果 III
中野智仁; 大橋政司; 大橋政司; 松林和幸; 上床美也; 巨海玄道
2009, 日本物理学会講演概要集, 64, 2, 1342-8349, 200902231618447832 - 近藤化合物CeAu2Si2の反強磁性に対する圧力効果
中野智仁; 酒井久美子; 巨海玄道; 松林和幸; 上床美也; 佐藤伊佐務; 小松原武美; 松本裕司; 青木晴善
2009, 日本磁気学会学術講演概要集, 33rd, 1882-2959, 201202232367884784 - 重い電子系β-YbAlB4における圧力下の超伝導と磁性
冨田崇弘; 久我健太郎; 堀江直樹; 松本洋介; 中辻知; 植田浩明; 松林和幸; 松本武彦; 上床義也
2009, 日本物理学会講演概要集, 64, 2, 1342-8349, 200902252159417744 - 28pTD-6 Pressure effect of CePtSi_2 II
NAKANO T; OHASHI M; MATSUBAYASHI K; UWATOKO Y; OOMI G
一般社団法人日本物理学会, 2009, Meeting Abstracts of the Physical Society of Japan, 64, 0, Japanese, 1342-8349, 110007371983 - Crystal structure analysis in pressure-induced commensurate magnetic phase of multiferroic HoMn2O5
H. Kimura; Y. Sakamoto; T. Yamazaki; Y. Noda; N. Aso; T. Fujiwara; K. Matsubayashi; Y. Uwatoko
2009, Activity Report on Neutron Scattering Research: Experimental Reports, 16, 783 - 28aPS-53 AgPdCu合金を用いた圧力セルの開発II(28aPS 領域8ポスターセッション(低温II(鉄砒素超伝導体,その他)),領域8(強相関系:高温超伝導,強相関f電子系など))
八板 克仁; 上床 美也; 松本 武彦; 諸冨 大樹; 和田 統; 吉田 靖雄; 稲垣 祐次; 河江 達也; 大橋 政司; 巨海 玄道; 松林 和幸
一般社団法人 日本物理学会, 2009, 日本物理学会講演概要集, 64, 0, Japanese, 110007371948 - 25pRG-11 Origin of the Valence Transition of SmS Revealed by Infrared and Terahertz Spectroscopy at High Pressure and Law Temperature
Mizuno T; Iizuka T; Matsubayashi K; Imura K; Suzuki H; Sato N. K; Kimura S
一般社団法人 日本物理学会, 2009, Meeting Abstracts of the Physical Society of Japan, 64, 0, Japanese, 110007497632 - β‐US2の磁性と伝導
池田修悟; 酒井宏典; 立岩尚之; 松田達磨; 目時直人; 金子耕士; 山本悦嗣; 中村彰夫; 芳賀芳範; 青木大; 本間佳哉; 杉山清寛; 大貫惇睦; 辺土正人; 松林和幸; 上床美也
01 Nov. 2008, 高圧討論会講演要旨集, 49th, 6, Japanese, 0917-6373, 200902274543315871 - 22pQC-9 Pressure Effect of Rare-earth Tri-telluride CeTe_3
Deguchi K.; Chen G. F.; Ban S.; Aso N.; Matsubayashi K.; Uwatoko Y.; Sato N. K.
The Physical Society of Japan (JPS), 25 Aug. 2008, Meeting abstracts of the Physical Society of Japan, 63, 2, 555-555, Japanese, 1342-8349, 110006984543, AA11439205 - 21aPS-79 Thermodynamic and transport properties and P-T phase diagram of a valence-fluctuating phase of SmS
Imura K.; Matsubayashi K.; Suzuki H. S.; Deguchi K.; Sato N. K.
The Physical Society of Japan (JPS), 25 Aug. 2008, Meeting abstracts of the Physical Society of Japan, 63, 2, 511-511, Japanese, 1342-8349, 110006984374, AA11439205 - Synthesis and physical properties of YbT_2Zn_<20> (T=Co, Rh, Ir)
SAIGA Yuta; MATSUBAYASHI Kazuyuki; FUJIWARA Tetsuya; KOSAKA Masashi; UWATOKO Yoshiya
22 May 2008, 希土類 = Rare earths, 52, 180-181, Japanese, 0910-2205, 10021085305, AN10379697 - ミュオンスピン緩和法によるYbCo2Zn20の磁性研究
髭本亘; 伊藤孝; 大石一城; 佐藤一彦; 才賀裕太; 小坂昌史; 松林和幸; 上床美也
29 Feb. 2008, 日本物理学会講演概要集, 63, 1, 633, Japanese, 1342-8349, 200902269666853220 - 26aWR-7 Magnetic and transport properties of the paramagnet β-US_2
Ikeda S; Sakai H; Tateiwa N; Matsuda T.D; Metoki N; Kaneko K; Aoki D; Homma Y; Yamamoto E; Nakamura A; Shiokawa Y; Ota Y; Sugiyama K; Matsubayashi K; Hedo M; Uwatoko Y; Haga Y; Onuki Y
The Physical Society of Japan (JPS), 29 Feb. 2008, Meeting abstracts of the Physical Society of Japan, 63, 1, Japanese, 1342-8349, 110007195556 - 26aWP-6 Magnetism of YbCo_2Zn_<20> probed by muon spin relaxation
Higemoto W; Ito T.U; Ohishi K; Satoh K; Saiga Y; Kosaka M; Matsubayashi K; Uwatoko Y
The Physical Society of Japan (JPS), 29 Feb. 2008, Meeting abstracts of the Physical Society of Japan, 63, 1, Japanese, 1342-8349, 110007195577 - Pressure and magnetic field effect on transport gap of black SmS
K. Imura; K. Matsubayashi; H. S. Suzuki; K. Deguchi; N. K. Sato
We measured the electrical resistivity of black SmS at high magnetic fields up to 30 T. We observed that the magnetic field drastically reduces the energy gap E-g(H, P) in a similar way to that the pressure does. From the finding that data points of E-g(H, P) lie on a single line as functions of H and P, we argue that the giant negative magnetoresistance is intrinsic to black SmS and the magnetic field plays a similar role to the pressure., IOP PUBLISHING LTD, 2008, JOINT 21ST AIRAPT AND 45TH EHPRG INTERNATIONAL CONFERENCE ON HIGH PRESSURE SCIENCE AND TECHNOLOGY, 121, 032014, English, Peer-reviwed, Report scientific journal, 1742-6588, 1742-6596, WOS:000303157800082 - Development of palm cubic anvil apparatus for low temperature physics
Yoshiya Uwatoko; Kazuyuki Matsubayashi; Takehiko Matsumoto; Naofumi Aso; Masakazu Nishi; Tetsuya Fujiwara; Masato Hedo; Satoshi Tabata; Katsunori Takagi; Masashi Tado; Hiroyuki Kagi
Effects of pressure on the physical properties are very important for understanding highly correlated electron systems, in which pressure-induced attractive phenomena such as superconductivity and magnetically ordered non-Fermi liquid have been observed. Up to now, many scientists have developed a lot of high pressure apparatus for each purpose. In this paper, we present the very small "palm cubic-anvil high-pressure apparatus" for precise electric transport measurements under high pressure up to 8 GPa. The most outstanding characteristic of this pressure cell is its compactness. This cell enables us to measure absolute values of electrical resistivity, magneto-resistance and Hall coefficient at various temperatures. The details of our palm cubic high-pressure apparatus are introduced, and some neutron experimental results at room temperature are discussed., 2008, Review of High Pressure Science and Technology/Koatsuryoku No Kagaku To Gijutsu, 18, 3, 230-236, Japanese, Book review, 0917-639X, 1348-1940, 50849109483 - 高圧下におけるCeAu2Si2(単結晶)の磁性と伝導 II
大村美央; 酒井久美子; 中野智仁; 松林和幸; 上床美也; 佐藤伊佐務; 松本裕司; 青木晴善; 小松原武美; 巨海玄道
2008, 日本物理学会講演概要集, 63, 2, 1342-8349, 200902296983101125 - 重い電子系YbAlB4における圧力誘起相転移
冨田崇弘; 久我健太郎; 久我健太郎; 松本洋介; 中辻知; 松林和幸; 上床美也
2008, 日本物理学会講演概要集, 63, 1, 1342-8349, 200902216429662006 - 重い電子系YbAlB4における圧力下の非フェルミ液体性
冨田崇弘; 久我健太郎; 松本洋介; 中辻知; 植田浩明; 上田寛; 松林和幸; 松本武彦; 松本武彦; 上床美也
2008, 日本物理学会講演概要集, 63, 2, 1342-8349, 200902285922082797 - 22pQC-10 Pressure effect of CePtSi_2
NAKANO T; OHASHI M; MATSUBAYASHI K; UWATOKO Y; OOMI G
一般社団法人日本物理学会, 2008, Meeting Abstracts of the Physical Society of Japan, 63, 0, Japanese, 1342-8349, 110006984544 - 21aPS-49 Magnetic and transport properties of CeAu_2Si_2 single crystal under high pressure II
OHMURA M; SAKAI K; NAKANO T; MATSUBAYASHI K; UWATOKO Y; SATOH I; MATSUMOTO Y; AOKI H; KOMATSUBARA T; OOMI G
一般社団法人日本物理学会, 2008, Meeting Abstracts of the Physical Society of Japan, 63, 0, Japanese, 1342-8349, 110006984346 - 23pQE-8 The development of pressure cell made of AgPdCu alloy
Yaita K; Uwatoko Y; Matsumoto T; Morodomi H; Wada O; Yoshida Y; Inagaki Y; Kawae T; Ohashi M; Oumi G; Matsubayasi K
The Physical Society of Japan, 2008, Meeting Abstracts of the Physical Society of Japan, 63, 0, Japanese, 110006984643 - 23aWR-2 Infrared and Terahertz Spectroscopy of SmS under Pressure
Mizuno T; Iizuka T; Matsubayashi K; Imura K; Suzuki H; Sato N.K; Kimura S
一般社団法人 日本物理学会, 2008, Meeting Abstracts of the Physical Society of Japan, 63, 0, Japanese, 110007195420 - 23pWD-7 Pressure Dependence of Chalcogenide Quasi-2D Triangular Antiferromagnets, FeGa_2S_4, Fe_2Ga_2S_5
Tomita T.; Tonomura H.; Nambu Y.; Matsumoto Y.; Nakatsuji S.; Maeno Y.; Matsubayashi K.; Uwatoko Y.
The Physical Society of Japan (JPS), 21 Aug. 2007, Meeting abstracts of the Physical Society of Japan, 62, 2, 499-499, Japanese, 1342-8349, 110007141372, AA11439205 - 22pXA-12 Magnetism and Superconductivity near Critical Point on UGe_2
Iijima R.; Ban S.; Imura K.; Matsubayashi K.; Deguchi K.; Sato N. K.
The Physical Society of Japan (JPS), 21 Aug. 2007, Meeting abstracts of the Physical Society of Japan, 62, 2, 617-617, Japanese, 1342-8349, 110007139614, AA11439205 - 22pXA-13 Pressure effect of the paramagnet β-US_2
Ikeda S; Sakai H; Matsuda T. D; Tateiwa N; Aoki D; Homma Y; Yamamoto E; Nakamura A; Shiokawa Y; Ota Y; Sugiyama K; Matsubayashi K; Hedo M; Uwatoko Y; Haga Y; Onuki Y
The Physical Society of Japan (JPS), 21 Aug. 2007, Meeting abstracts of the Physical Society of Japan, 62, 2, Japanese, 1342-8349, 110007139615 - 20pWP-8 Specific heat under pressure of La diluted Ce_<1-x>La_xRhIn_5
Wakishima K.; Matsubayashi K.; Deguchi K.; Sato N. K.
The Physical Society of Japan (JPS), 28 Feb. 2007, Meeting abstracts of the Physical Society of Japan, 62, 1, 633-633, Japanese, 1342-8349, 110007139315, AA11439205 - SmSの高圧下赤外・テラヘルツ反射分光
水野貴文; 木村真一; 木村真一; 松林和幸; 井村敬一郎; 鈴木博之; 佐藤憲昭
30 Oct. 2006, 高圧討論会講演要旨集, 47th, 109, Japanese, 0917-6373, 200902219977446221 - 23pPSB-35 Magnetoresistance and Hall effect measurements on SmS under pressure
Imura K.; Matsubayashi K.; Suzuki H.S.; Deguchi K.; Sato N.K.
The Physical Society of Japan (JPS), 18 Aug. 2006, Meeting abstracts of the Physical Society of Japan, 61, 2, 427-427, Japanese, 1342-8349, 110007182789, AA11439205 - 27pTC-2 Hall effect measurements on SmS
Imura K.; Matsubayashi K.; Suzuki H.S.; Deguchi K.; Sato N.K.
The Physical Society of Japan (JPS), 04 Mar. 2006, Meeting abstracts of the Physical Society of Japan, 61, 1, 552-552, Japanese, 1342-8349, 110007177833, AA11439205 - 28pPSA-46 Infrared Spectroscopy of SmS under Pressures
Kimura S; Mizuno T; Matsubayashi K; Imura K; Suzuki H; Sato N.K
一般社団法人 日本物理学会, 2006, Meeting Abstracts of the Physical Society of Japan, 61, 0, Japanese, 110007180616 - 27pTC-3 Three-Dimensional Angle-resolved Photoemission Spectroscopy on SmS
Ito T; Im H.J; Chainani A; Matsubayashi K; Kimura S; Kim H.-D; Imura K; Suzuki H; Sato N.K
一般社団法人 日本物理学会, 2006, Meeting Abstracts of the Physical Society of Japan, 61, 0, Japanese, 110007180997 - 23pPSB-34 Infrared and Terahertz Spectroscopy of SmS under Pressure
Mizuno T; Kimura S; Matsubayashi K; Imura K; Suzuki H; Sato N.K
一般社団法人 日本物理学会, 2006, Meeting Abstracts of the Physical Society of Japan, 61, 0, Japanese, 110007182591 - 19pPSA-45 Electrical transport measurement on SmS under pressure
Imura K.; Matsubayashi K.; SUzuki H.; Deguchi K.; Sato N. K.
The Physical Society of Japan (JPS), 19 Aug. 2005, Meeting abstracts of the Physical Society of Japan, 60, 2, 404-404, Japanese, 1342-8349, 110004539016, AA11439205 - 19pPSA-44 Physical properties of SmS under pressure
Matsubayashi K.; Imura K.; Chen G.; Suzuki H. S.; Deguchi K.; Sato N. K.
The Physical Society of Japan (JPS), 19 Aug. 2005, Meeting abstracts of the Physical Society of Japan, 60, 2, 404-404, Japanese, 1342-8349, 110004539015, AA11439205 - 19pPSA-54 Physical Properties of (La, Ce)RhIn_5
Tokuda N.; Chen G.; Nishioka T.; Matsubayashi K.; Deguchi K.; Sato K.
The Physical Society of Japan (JPS), 19 Aug. 2005, Meeting abstracts of the Physical Society of Japan, 60, 2, 406-406, Japanese, 1342-8349, 110004539025, AA11439205 - 25aPS-78 Physical property measurements on SmS under magnetic field
Imura K.; Matsubayashi K.; Suzuki H.; Sato N.K.
The Physical Society of Japan (JPS), 04 Mar. 2005, Meeting abstracts of the Physical Society of Japan, 60, 1, 540-540, Japanese, 1342-8349, 110004536181, AA11439205 - 28pPSA-71 Thermal Expansion measurements under pressure of UGe_2
Ito A; Matsubasyshi K; Nakane H.; Motoyama G; Nishioka T; Sato N K
The Physical Society of Japan (JPS), 03 Mar. 2004, Meeting abstracts of the Physical Society of Japan, 59, 1, 618-618, Japanese, 1342-8349, 110002194571, AA11439205 - Pressure dependence of superconducting transition temperature of URu_2Si_2
Uemura S.; Nakakne H.; Matsubayashi K.; Motoyama G.; Nishioka T.; Sato N.K.
The Physical Society of Japan (JPS), 15 Aug. 2003, Meeting abstracts of the Physical Society of Japan, 58, 2, 538-538, Japanese, 1342-8349, 110002062231, AA11439205 - Magnetic properties - Parasitic ferromagnetism in a hexaboride?
K Matsubayashi; M Maki; T Tsuzuki; T Nishioka; NK Sato
NATURE PUBLISHING GROUP, Nov. 2002, NATURE, 420, 6912, 143-144, English, Peer-reviwed, Report scientific journal, 0028-0836, WOS:000179200900034 - Unusual behavior in specific heat of the semiconducting SmS
Matsubayashi K.; Mukai H.; Tsuzuki T.; Nishioka T.; Sato K.
The Physical Society of Japan (JPS), 13 Aug. 2002, Meeting abstracts of the Physical Society of Japan, 57, 2, 374-374, Japanese, 1342-8349, 110009718336, AA11439205 - 24aXF-5 Magnetic Properties of CaB_6
Maki M.; Matsubayashi K.; Tsuzuki T.; Nishioka T.; Sato N. K.
The Physical Society of Japan (JPS), 01 Mar. 2002, Meeting abstracts of the Physical Society of Japan, 57, 1, 368-368, Japanese, 1342-8349, 110009771673, AA11439205
Books and other publications
- 日本物理学会誌
松林和幸; 上床美也
Japanese, Joint work, 日本物理学会, May 2018 - 高圧力の科学と技術
松林和幸; 上床美也
Japanese, Joint work, 良質な高圧力環境下で開拓された強相関電子系物質における圧力誘起超伝導, 高圧力学会, 01 Mar. 2016 - パリティ
松林和幸
Japanese, Single work, ｎｅｗｓ：マンガン系物質で初めての圧力誘起超伝導, 丸善出版, 25 Dec. 2015 - 高圧力の科学と技術
松林和幸; 久田旭彦; 河江達也; 上床美也
Japanese, Joint work, 高圧力発生装置の小型化による物性測定環境の拡張, 高圧力学会, 2012 - 高圧力の科学と技術
北川健太郎; 松林和幸; 後藤弘匡; 松本武彦; 上床美也; 八木健彦; 瀧川仁
Japanese, Joint work, 容積効率にこだわった高圧セルによる10 GPa級NMR測定, 高圧力学会, 2012 - 日本物理学会誌
松林和幸; 松本武彦; 上床美也; 辺土正人
Japanese, Joint work, 静水圧下の低温物性測定技術, 日本物理学会, 2011
Lectures, oral presentations, etc.
- ファンデルワールス層状物質CeTe2Seの高圧相図
栗原 蒼志; 斎藤 颯汰; 植田 大地; 松林 和幸
Poster presentation, 第65回高圧討論会, Peer-reviewed
14 Nov. 2024 - 近藤半金属CeRu2Al10の高圧下電子輸送特性Ⅱ
薦田拓也; 前谷風弥; 松岡英一; 小手川恒; 藤秀樹; 松林和幸; D.Bhoi; 沈晓玲; 上床美也; 菅原仁
Poster presentation, 日本物理学会第79回年次大会, Peer-reviewed
18 Sep. 2024 - ベクトルパルスマグネットを用いた回転パルス磁場の発生とHOPGの異方的磁気抵抗測定
野田孝祐; 池田暁彦; 関健汰; 松林和幸; 秋葉和人
Oral presentation, 日本物理学会第79回年次大会, Peer-reviewed
17 Sep. 2024 - スピネル型化合物CuRh2S4の電気伝導特性と超伝導の圧力効果
唐澤知大; 松本凛之介; 江見方敏; 片山尚幸; 澤博; 松林和幸
Oral presentation, 日本物理学会第79回年次大会, Peer-reviewed
17 Sep. 2024 - 精密な高圧力制御と物性計測で拓く圧力誘起超伝導
松林和幸
Invited oral presentation, 未来を拓く高圧力科学技術セミナーシリーズ（48） 「高圧力を用いた超伝導体の合成と計測技術」, Invited, Peer-reviewed
21 Aug. 2024 - 高圧力下・極低温におけるYbRh2Zn20の熱電能および交流比熱測定
鈴木雄大; 工藤一輝; 橘高俊一郎; 辺土正人; 上床美也; 松林和幸
Oral presentation, Japanese, 日本物理学会 2024年春季大会, Peer-reviewed
19 Mar. 2024 - 重い電子系物質YbT2Zn20 (T = Co, Rh)における熱電特性の高圧力制御
鈴木雄大; 工藤一輝; 辺土正人; 上床美也; 松林和幸
Oral presentation, Japanese, 第64回高圧討論会, Peer-reviewed
03 Nov. 2023 - 高圧下精密交流比熱測定技術の開発及びCeCoIn5の超伝導転移における圧力効果の検証
竹内將暁; 辻貴丹; 加藤謙介; 河野洋平; 橘高俊一郎; 松林和幸A; 北川健太郎; 上床美也; 榊原俊郎
Oral presentation, 日本物理学会第78回年次大会, Peer-reviewed
19 Sep. 2023
Sep. 2023 - 熱電能からみたYbT2Zn20 (T = Co, Rh)の高圧力下・極低温物性
鈴木雄大; 工藤一輝; 辺土正人; 上床美也; 松林和幸
Poster presentation, 日本物理学会第78回年次大会, Peer-reviewed
18 Sep. 2023
Sep. 2023 - 希釈冷凍機域における圧力下交流比熱の精密定量測定実現に向けての研究
河野洋平; 辻貴丹; 加藤謙介; 竹内將暁; 北川健太郎A; 松林和幸; 上床美也; 榊原俊郎; 橘高俊一郎
Poster presentation, 日本物理学会第78回年次大会, Peer-reviewed
18 Sep. 2023
Sep. 2023 - スピネル型化合物CuIr2Se4の高圧下放射光X線構造解析
江見方敏; 小島慶太; 片山尚幸; 松林和幸; 岡健太; 門林宏和; 河口沙織; 澤博
Poster presentation, 日本物理学会第78回年次大会, Peer-reviewed
18 Sep. 2023
Sep. 2023 - CuRh2X4(X=S,Se)の高圧力下電気抵抗・Hall効果測定
唐澤知大; 松本凛之介; 江見方敏; 片山尚幸; 澤博; 松林和幸
Poster presentation, 日本物理学会第78回年次大会, Peer-reviewed
18 Sep. 2023
Sep. 2023 - 遷移金属ジルコナイドRhZr2における高圧下電気抵抗と異方的圧縮
有馬寛人; 渡邊雄翔; 山岡人志; 松林和幸B; 山下愛智; 水口佳一
Poster presentation, 日本物理学会第78回年次大会, Peer-reviewed
18 Sep. 2023
Sep. 2023 - 高圧力下における重い電子系物質YbT2Zn20(T=Co，Rh)の熱電能
鈴木雄大, 辺土正人, 上床美也, 松林和幸
Poster presentation, 日本物理学会春季大会, Peer-reviewed
24 Mar. 2023
Mar. 2023 - 2Dファンデルワールス結晶CrSiTe3の高圧下超伝導と磁性
平岡奈緒香; 荒井悠太郎; 松林和幸; 北川健太郎; 高木英典
Oral presentation, 日本物理学会春季大会, Peer-reviewed
24 Mar. 2023
Mar. 2023 - CuRh2Se4の高圧下における超伝導相を含む低対称化相の発見
江見方敏; 小島慶太; 塩見学; 片山尚幸; 松林和幸; 門林宏和; 平尾直久; 河口沙織; 澤博
Oral presentation, 日本物理学会春季大会, Peer-reviewed
23 Mar. 2023
Mar. 2023 - 重い電子系物質YbCo2Zn20の極低温・高圧下における熱物性測定
鈴木雄大; 工藤一輝; 辺土正人; 上床美也; 松林和幸
Poster presentation, Japanese, 日本物理学会秋季大会
14 Sep. 2022 - 2次元ハニカム強磁性体CrSiTe3の高圧下磁化
平岡奈緒香; 荒井悠太郎; 松林和幸; 北川健太郎; 高木英典
Oral presentation, Japanese, 日本物理学会秋季大会
13 Sep. 2022 - Smテルライドでのキタエフ候補物質開発II
北川健太郎; 露木裕太; 土場優雅; 矢田季寛; 小島慶太; 片山尚幸; 松林和幸; 高木英典
Oral presentation, Japanese, 日本物理学会秋季大会
13 Sep. 2022 - Ba2MgReO6における四極子秩序と磁気秩序の圧力効果
有馬寛人; 大下宜晃; 平井大悟郎; 廣井善二; 松林和幸
Oral presentation, Japanese, 日本物理学会 第77回年次大会
17 Mar. 2022 - 層状構造を有するナローギャップ半導体における圧力誘起超伝導
松林和幸
Invited oral presentation, Japanese, ISSPワークショップ 高圧セミナー “最近の話題から”, Domestic conference
05 Mar. 2022 - Pressure Induced Excitonic Insulator-to-Semimetal Transition in Ta2NiSe5 Studied by Optical Conductivity
Hidekazu Okamura; Kazuyuki Matsubayashi; Takashi Mizokawa; Yangfan Lu; Naoyuki Katayama; Minoru Nohara; Hidenori Takagi; Yuka Ikemoto; Taro Moriwaki
Oral presentation, English, 10th Asian Conference on High Pressure Research, International conference
23 Nov. 2021 - PrRu2Sn2Zn18における四極子秩序の磁場・圧力効果
山本洸凪; 駒形貴裕; 脇舎和平; 梅原出; 郷地順; 上床美也; 松林和幸
Poster presentation, Japanese, 日本物理学会秋季大会
21 Sep. 2021 - ナローギャップ半導体Ta2NiS5における高圧力下ホール効果測定
有馬寛人; 片山尚幸; 澤博; 野原実; 魯楊帆; 北川健太郎; 高木英典; 上床美也; 松林和幸
Poster presentation, Japanese, 日本物理学会秋季大会
20 Sep. 2021 - BiS2系層状化合物の単結晶試料における高圧力下電気伝導測定
有馬寛人; Y. Yuan; 成田傑; 工藤一輝; 矢藤優佑; Rajveer Jha; 後藤陽介; 水口佳一; 東中隆二; 松田達麿; 青木勇二; 松林和幸
Oral presentation, Japanese, 日本物理学会 第76回年次大会, Domestic conference
14 Mar. 2021 - PrTi2Al20の強四極子秩序が消失した高圧域での非フェルミ液体的挙動
山本洸凪; 元山史都; 曾我部尚希; 磯前貴央; 酒井明人; 中辻知; 北川健太郎; 上床美也; 松林和幸
Oral presentation, Japanese, 日本物理学会 第76回年次大会, Domestic conference
12 Mar. 2021 - Gd5Ge4の磁気熱量効果
高野尚志; 梅原出; 上原政智; 石渡信吾; 上床美也; 郷地順; 松林和幸
Poster presentation, Japanese, 日本物理学会 第76回年次大会, Domestic conference
12 Mar. 2021 - BiS2系類縁化合物における圧力誘起超伝導
松林和幸; 有馬寛人; YAHUA Yuan; 内藤康氏; JHA Rajveer; 後藤陽介; 水口佳一; 松田達麿; 青木勇二
Oral presentation, Japanese, 第61回高圧討論会, Domestic conference
02 Dec. 2020 - BiS2系層状化合物における圧力誘起半導体-半金属転移と超伝導
有馬寛人; Y. Yuan; 内藤康氏; 工藤一輝; 矢藤優佑; Rajveer Jha; 後藤陽介; 水口佳一; 東中隆二; 松田達麿; 青木勇二; 松林和幸
Oral presentation, Japanese, 日本物理学会秋季大会, Domestic conference
11 Sep. 2020 - 高圧力下におけるPrTi2Al20の重い電子超伝導
山本洸凪; 元山史都; 曾我部尚希; 磯前貴央; 酒井明人; 中辻知; 北川健太郎; 上床美也; 松林和幸
Poster presentation, Japanese, 日本物理学会秋季大会, Domestic conference
08 Sep. 2020 - BiS2系層状化合物の温度-圧力相図
有馬寛人; Y. Yuan; 内藤康氏; 工藤一輝; 矢藤優佑; Rajveer Jha; 後藤陽介; 水口佳一; 松田達麿; 青木勇二; 松林和幸
Oral presentation, Japanese, 日本物理学会 第75回年次大会
19 Mar. 2020 - PrRu2Sn2Zn18における四極子秩序の圧力効果
山本洸凪; 駒形貴裕; 脇舎和平; 梅原出; 郷地順; 上床美也; 松林和幸
Oral presentation, Japanese, 日本物理学会 第75回年次大会
17 Mar. 2020 - 高圧力下・極低温・磁場中におけるYbCo2Zn20の熱電能
工藤一輝; 内藤康氏; 有馬寛人; 上床美也; 松林和幸
Oral presentation, Japanese, 日本物理学会 第75回年次大会
16 Mar. 2020 - Pr1-2-20 系の超伝導と重い電子状態、非フェルミ液体状態に対 する圧力効果
松林和幸
Oral presentation, Japanese, J-Physics:多極子伝導系の物理 令和元年度領域全体会議, Domestic conference
08 Jan. 2020 - High-pressure Hall effect measurement on Ta2NiSe5 as a candidate for excitonic insulator
H. Arima; Y. Naito; K. Kudo; N. Katayama; H. Sawa; M. Nohara; Y. Lu; K. Kitagawa; H. Takagi; Y. Uwatoko; K. Matsubayashi
Poster presentation, English, International Conference on Strongly Correlated Electron Systems 2019 (SCES '19), International conference
24 Sep. 2019 - Pressure-induced heavy fermion superconductivity and non-Fermi liquid behavior in non-Kramers doublet system PrT2Al20 (T = Ti, V)
Kazuyuki Matsubayashi
Invited oral presentation, English, International Conference on Strongly Correlated Electron Systems 2019 (SCES '19), Invited, International conference
24 Sep. 2019 - Effect of pressure on the quadrupolar and magnetic order in cubic double perovskite Ba2MgReO6
H. Arima; D. Hirai; Z. Hiroi; K. Matsubayashi
Poster presentation, English, J-Physics 2019 International Conference, International conference
20 Sep. 2019 - AC specific heat measurement of PrTi2Al20under pressure
R. Hoshi; F. Motoyama; R. Kuwata; S. Kittaka; Y. Uwatoko; N. Sokabe; A. Sakai; S. Nakatsuji; K. Kitagawa; K. Matsubayashi
Poster presentation, English, J-Physics 2019 International Conference, International conference
20 Sep. 2019 - LaOBiPbS3およびLa2O2Bi3AgS6における圧力誘起超伝導と高圧下における電気輸送特性
内藤康氏; 工藤一輝; 有馬寛人; 辺土正人; Rajveer Jha; 後藤陽介; 松田達磨; 青木勇二; 水口佳一; 松林和幸
Poster presentation, Japanese, 日本物理学会秋季大会
12 Sep. 2019 - 高圧下における熱電能測定法の開発とYbCo2Zn20への応用
工藤一輝; 内藤康氏; 有馬寛人; 上床美也; 松林和幸
Poster presentation, Japanese, 日本物理学会秋季大会
12 Sep. 2019 - 立方晶PrRu2Sn2Zn18の多極子秩序
脇舎和平; 駒形貴裕; 杉山雄紀; 上原政智; 郷地順; 松林和幸; 上床美也; 梅原出
Oral presentation, Japanese, 日本物理学会秋季大会
10 Sep. 2019 - Resistive anisotropy of candidate excitonic insulator Ta2NiSe5 under pressure
H. Arima; Y. Naito; K. Kudo; N. Katayama; H. Sawa; M. Nohara; Y. F. Lu; K. Kitagawa; H. Takagi; Y. Uwatoko; K. Matsubayashi
Poster presentation, English, The 27th AIRAPT International Conference on High Pressure Science and Technology (AIRAPT27)
09 Aug. 2019 - PrT2Al20 (T = Ti, V)における圧力誘起重い電子超伝導と非フェルミ液体的挙動
松林和幸
Oral presentation, Japanese, J-Physics 地域研究会, Domestic conference
28 Jun. 2019 - Effect of pressure on heavy fermion superconductivity in the quadrupole system PrTi2Al20
Kazuyuki Matsubayashi
Invited oral presentation, English, International workshop on Spin-Orbit Interaction and G-factor (SOIG 2019), Invited, International conference
10 May 2019 - 高圧下におけるTa2NiSe5の輸送特性
有馬寛人; 内藤康氏; 工藤一輝; 片山尚幸; 澤博; 野原実; 魯楊帆; 北川健太郎; 高木英典; 上床美也; 松林和幸
Poster presentation, Japanese, 日本物理学会 第74回年次大会, Domestic conference
15 Mar. 2019 - PrTi2Al20における高圧下交流比熱測定
星竜二; 元山史都; 桑田凌; 曽我部尚希; 磯前貴央; 酒井明人; 中辻知; 橘高俊一郎; 上床美也; 北川健太郎; 松林和幸
Poster presentation, Japanese, 日本物理学会 第74回年次大会, Domestic conference
14 Mar. 2019 - 高圧下における熱電能測定装置の開発
内藤康氏; 工藤一輝; 有馬寛人; 辺土正人; 松林和幸
Poster presentation, Japanese, 日本物理学会 第74回年次大会, Domestic conference
14 Mar. 2019 - Pressure-tuning of the interplay between ferroquadrupole order and superconductivity in PrTi2Al20
K. Matsubayashi; F. Motoyama; R. Hoshi; N. Sokabe; T. Isomae; M. Tsujimoto; A. Sakai; S. Nakatsuji; S. Kittaka; Y. Uwatoko; K. Kitagawa
Poster presentation, English, “Topological Phases and Functionality of Correlated Electron Systems” (TPFC2019), International conference
18 Feb. 2019 - PrTi2Al20の高圧下で顕在化する非フェルミ液体的挙動と超伝導の相関
元山史都; 曽我部尚希; 酒井明人; 中辻知; 北川健太郎; 上床美也; 松林和幸
Poster presentation, Japanese, 日本物理学会秋季大会, Domestic conference
11 Sep. 2018 - YbCo2Ge4の圧力－温度－磁場相図
桑田凌; 岩谷誠A; 北川健太郎B; 上床美也; 松林和幸
Poster presentation, Japanese, 日本物理学会秋季大会, Domestic conference
11 Sep. 2018 - 圧力下における交流法比熱測定装置の開発
星竜二; 橘高俊一郎; 上床美也; 松林和幸
Poster presentation, Japanese, 日本物理学会秋季大会, Domestic conference
11 Sep. 2018 - CeCu6-yAuyのCe希釈系における交流磁化率の奇妙な振る舞い
椎野貴之; 壁谷典幸; 井村敬一郎; 出口和彦; 佐藤憲昭; 木村憲彰; 落合明; 松林和幸
Poster presentation, Japanese, 日本物理学会秋季大会, Domestic conference
11 Sep. 2018 - 重い電子系化合物YbCo2Zn2の置換系物質の物性
津堅涼; 高村治希; 岩下大空; 嘉数幸二; 大岡辰也; 久手堅貴太; 玉城豪士; 小濱徳史; 比嘉泰之; 小林理気; 阿曽尚文; 松林和幸; 上床美也
Poster presentation, Japanese, 日本物理学会秋季大会, Domestic conference
11 Sep. 2018 - Ta2NiSe5の相図における静水圧と異方的圧力効果の比較
有馬寛人; 片山尚幸; 野原実; 魯楊帆; 北川健太郎; 高木英典; 上床美也; 松林和幸
Poster presentation, Japanese, 日本物理学会秋季大会, Domestic conference
10 Sep. 2018 - SmPtSi2の試料作成と基礎物性
山口嵩人; 高橋英亮; 中野智仁; 武田直也; 松林和幸; 上床美也; K. Uhlirova; J. Pronkleska; V. Sechovsky
Poster presentation, Japanese, 日本物理学会秋季大会, Domestic conference
10 Sep. 2018 - 高圧力による新規超伝導体の探索と電子状態の制御
松林和幸
Invited oral presentation, Japanese, J-Physics トピカルミーティング ものづくりシリーズ第3回「物質探索最前線」, Invited, Domestic conference
07 Aug. 2018 - Pressure-induced novel superconductivity and quantum critical phenomena in nonmagnetic systems
K. Matsubayashi
Invited oral presentation, English, Joint Eighteenth International Conference on HIGH PRESSURE SEMICONDUCTOR PHYSICS & Second International Workshop on HIGH PRESSURE STUDY OF SUPERCONDUCTORS (HPSP18&WHS2), Invited, International conference
27 Jul. 2018 - 高圧力を用いた新奇な量子相転移と超伝導の探索
松林和幸
Invited oral presentation, Japanese, 京都大学基礎物理学研究所研究会「電子相関が生み出す新規な秩序と超伝導現象:トポロジー、液晶状態、動的現象」, Domestic conference
09 May 2018 - High-pressure tuning of the quadrupole order and superconductivity in PrTr2Al20 (Tr = Ti, V)
K. Matsubayashi
Invited oral presentation, English, International Workshop: Novel Phenomena in Quantum Materials driven by Multipoles and Topology High, Invited, International conference
10 Apr. 2018 - 高圧力によって誘起される強相関電子系物質の新奇な量子相転移
松林和幸
Invited oral presentation, Japanese, 第61回化合物新磁性材料専門研究会 高圧力技術を利用した超伝導研究, Invited, Domestic conference
26 Mar. 2018 - 高圧下におけるPrTi2Al20の超伝導と非フェルミ液体的挙動
元山史都; 辻本真規; 酒井明人; 中辻知; 北川健太郎; 上床美也; 松林和幸
Oral presentation, Japanese, 日本物理学会 第73回年次大会, 東京理科大学（野田キャンパス）, Domestic conference
25 Mar. 2018 - 重い電子系化合物Yb(Co1-xIrx)2Zn20の物性
瑞慶覧長星; 佐藤信; 高村治希; 小林理気; 阿曽尚文; 植田大地; 池田陽一; 吉田雅洋; 吉澤英樹; 松林和幸; 郷地順; 上床美也
Poster presentation, Japanese, 日本物理学会 第73回年次大会, 東京理科大学（野田キャンパス）, Domestic conference
23 Mar. 2018 - 励起子絶縁体候補物質Ta2NiSe5における高圧下ホール効果
有馬寛人; 片山尚幸; 野原実; 魯楊帆; 高木英典; 上床美也; 松林和幸
Oral presentation, Japanese, 日本物理学会 第73回年次大会, 東京理科大学（野田キャンパス）, Domestic conference
22 Mar. 2018 - YbCo2Ge4における非フェルミ液体的挙動とメタ磁性の圧力効果
桑田凌; 岩谷誠; 北川健太郎; 上床美也; 松林和幸
Oral presentation, Japanese, 日本物理学会 第73回年次大会, 東京理科大学（野田キャンパス）, Domestic conference
22 Mar. 2018 - High pressure studies of quadrupole order and superconductivity in PrT2Al20 (T=Ti, V)
K. Matsubayashi; F. Motoyama; M. Tsujimoto; A. Sakai; S. Nakatsuji; Y. Uwatoko; K. Kitagawa
Poster presentation, Japanese, J-Physics Annual Meeting FY2017
16 Mar. 2018 - Pressure tuning of quadrupole order, superconductivity and non-Fermi liquid behavior in PrT2Al20 (T = Ti, V)
K. Matsubayashi
Invited oral presentation, English, J-Physics Topical Meeting: Exotic Phenomena in Itinerant Multipole Systems, Invited, International conference
18 Dec. 2017 - 励起子絶縁体候補物質Ta2NiSe5における高圧下電気抵抗とホール効果
有馬寛人; 片山尚幸; 野原実; 魯楊帆; 高木英典; 上床美也; 松林和幸
Poster presentation, Japanese, 日本物理学会 2017年秋季大会, Domestic conference
23 Sep. 2017 - PrTi2Al20における強四極子秩序と超伝導の圧力効果
元山史都; 辻本真規; 酒井明人; 中辻知; 北川健太郎; 上床美也; 松林和幸
Poster presentation, Japanese, 日本物理学会 2017年秋季大会, Domestic conference
22 Sep. 2017 - YbCo2Ge4における圧力誘起磁気秩序
桑田凌; 岩谷誠; 北川健太郎; 上床美也; 松林和幸
Poster presentation, Japanese, 日本物理学会 2017年秋季大会, Domestic conference
21 Sep. 2017 - Pressure-temperature phase diagram of possible excitonic insulator Ta2NiSe5
K. Matsubayashi
Invited oral presentation, English, E-MRS 2017 Fall Meeting, Invited, International conference
18 Sep. 2017 - Novel phase diagram in antiferroquadrupolar PrV2Al20 under pressure and magnetic field
K. Matsubayashi; M. Tsujimoto; A. Sakai; S. Nakatsuji; Y. Uwatoko; K. Kitagawa
Poster presentation, English, SCES 2017, International conference
19 Jul. 2017 - PrT2Al20 (T = Ti, V)における四極子秩序と超伝導の圧力効果
松林和幸
Invited oral presentation, Japanese, J-Physics トピカルミーティング「局在多極子と伝導電子の相関による新現象」, Invited, Domestic conference
17 Apr. 2017 - 4f 電子系物質における圧力誘起量子臨界現象
松林和幸
Invited oral presentation, Japanese, 高圧力と量子ビームのマリアージュによる新規物性分野開拓の物質科学研究会, Invited, Domestic conference
25 Mar. 2017 - Pressure-induced superconductivity in EuFBiS2 single crystal
Yahua Yuan; 松林和幸; 梶谷丈; 東中隆二; 松田達磨; 木勇二
Oral presentation, Japanese, 日本物理学会 第72回年次大会, Domestic conference
18 Mar. 2017 - 反強四極子秩序を示すPrV2Al20の高圧下における磁場ー温度相図と非フェルミ液体的振る舞い
松林和幸; 辻本真規; 酒井明人; 中辻知; 上床美也; 北川健太郎
Oral presentation, Japanese, 日本物理学会, Domestic conference
13 Sep. 2016 - Pressure-induced heavy fermion superconductivity in PrT2Al20 (T = Ti, V)
K. Matsubayashi
Invited oral presentation, English, The 17th International Conference on High Pressure in Semiconductor Physics (HPSP-17) & Workshop on High-pressure Study on Superconducting (WHS), International conference
08 Aug. 2016 - Quantum Criticality and Superconductivity in Non-magnetic Quadrupolar System PrT2Al20 (T=Ti, V)
K. Matsubayashi
Invited oral presentation, English, Rare Earths 2016, International conference
08 Jun. 2016 - PrT2Al20 (T = Ti, V)における四極子秩序と超伝導の圧力効果
松林和幸
Invited oral presentation, Japanese, 新学術領域研究J-Physics:多極子伝導系の物理 平成28年度領域全体会議, Domestic conference
28 May 2016 - PrV2Al20の高圧下・磁場中における非フェルミ液体的振る舞い
松林和幸; 辻本真規; 中辻知; 上床美也; 北川健太郎
Poster presentation, Japanese, 日本物理学会 第 71 回年次大会, Domestic conference
22 Mar. 2016 - 強相関電子系物質における多自由度に起因する圧力誘起量子相転移の研究
松林和幸
Invited oral presentation, Japanese, 日本物理学会 第 71 回年次大会, Invited, Domestic conference
21 Mar. 2016 - 籠状Pr1-2-20系化合物における四極子秩序と超伝導
松林和幸
Invited oral presentation, Japanese, Workshop: CROSSroads of Users and J-PARC 第13回「強相関電子系の物理」, Invited, Domestic conference
03 Dec. 2015 - Ta2NiSe5 における圧⼒誘起半導体-半金属転移と超伝導
松林和幸
Invited oral presentation, Japanese, 物性研究所短期研究会 低次元電子系におけるエキシトニック相の新展開, Invited, Domestic conference
26 Nov. 2015 - Heavy fermion superconductivity and non-Fermi liquid behavior in PrT2Al20 (T=Ti, V) under pressure
K. Matsubayashi
Invited oral presentation, Japanese, Toyota RIKEN International Workshop 2015, Invited, International conference
17 Nov. 2015 - Yb系新物質YbCo2Ge4における圧力効果
松林和幸; 北川健太郎; 岩谷誠; 河村直己; 水牧仁一朗; 石松直樹; 渡辺真仁; 上床美也
Poster presentation, Japanese, 第56回高圧討論会, Domestic conference
11 Nov. 2015 - Ta2NiSe5における圧力効果:圧力誘起半導体-金属転移と超伝導
松林和幸
Invited oral presentation, Japanese, Workshop: CROSSroads of Users and J-PARC第16回「電子物性研究とその将来」, Domestic conference
15 Oct. 2015 - Pressure-temperature phase diagram of PrT2Al20 (T = Ti, V): Interplay between quadrupole order and superconductivity
K. Matsubayashi
Invited oral presentation, English, TMU International Symposium on “New Quantum Phases Emerging from Novel Crystal Structure”, International conference
25 Sep. 2015 - PrV2Al20の反強四極子秩序と超伝導の圧力効果
松林和幸; 鈴木淳一郎; 辻本真規; 中辻知; 上床美也; 北川健太郎
Oral presentation, Japanese, 日本物理学会 2015 秋季大会
18 Sep. 2015 - Ta2NiSe5における圧力誘起半導体-金属転移と超伝導
松林和幸
Invited oral presentation, Japanese, 日本物理学会「第70回年次大会 」, Domestic conference
22 Mar. 2015 - 良質な高圧力環境下で開拓された強相関電子系物質における圧力誘起超伝導
松林和幸
Invited oral presentation, Japanese, 未来を拓く高圧力科学技術セミナーシリーズ（40）「良質高圧力に支えられた物理学」, Invited, Domestic conference
10 Feb. 2015 - Pressure-induced Quantum Critical Phenomena in Heavy Fermion systems
K. Matsubayashi
Invited oral presentation, English, 7th Asian Conference on High Pressure Research (ACHPR-7), Invited, International conference
16 Jan. 2015 - PrT2Al20 (T=Ti, V)における四極子秩序と圧力誘起重い電子超伝導
松林和幸
Invited oral presentation, Japanese, 基研研究会「多自由度電子状態と電子相関が生み出す新奇超伝導の物理」, Invited, Domestic conference
22 Oct. 2014 - Experimental situation in Kondo lattice and relevant materials
松林和幸
Invited oral presentation, Japanese, 日本物理学会「秋季大会」Division 6•4•8 Joint Symposium Odd-frequency pairing - current status -, Invited, Domestic conference
07 Sep. 2014 - Pressure tuned quadrupole order and heavy fermion superconductivity in PrTr2Al20 (Tr = Ti, V)
K. Matsubayashi
Invited oral presentation, English, The International Conference on Strongly Correlated Electron Systems (SCES), Invited, International conference
07 Jul. 2014 - 四極子秩序を示すPrTi2Al20における圧力誘起重い電子系超伝導
松林和幸
Invited oral presentation, Japanese, 第54回高圧討論会 高圧力と超伝導シンポジウム, Domestic conference
16 Nov. 2013 - Study of Pressure-induced Superconductivity with a Large-Volume Multianvil Device
K. Matsubayashi
Invited oral presentation, English, International Conference on High Pressure Science and Technology, International conference
26 Sep. 2011
Courses
- Applied Physics Laboratory Ⅱ
Present
The University of Electro-Communications - Physics Laboratory
Present
The University of Electro-Communications - Advanced Lectures on Electronic Properties in Solids
Present
The University of Electro-Communications - Thermodynamics
Present
The University of Electro-Communications - Analytical Dynamics
Present
The University of Electro-Communications - 応用物理工学実験第二
電気通信大学 - 固体物理工学第二
The University of Electro-Communications - 先進理工学基礎
電気通信大学 - 総合コミュニケーション科学
電気通信大学
Research Themes
- 高圧力制御と精密物性測定による特異な熱電特性の開拓
松林 和幸
日本学術振興会, 科学研究費助成事業, 電気通信大学, 基盤研究(C), 25K07222
01 Apr. 2025 - 31 Mar. 2028 - 無機柔粘性結晶の構造的特徴を活用した革新的物質機能の開拓
片山 尚幸; 小島 慶太; 松林 和幸; 杉本 高大
日本学術振興会, 科学研究費助成事業, 名古屋大学, 基盤研究(B), 24K01329
Apr. 2024 - Mar. 2027 - Development of Kitaev Honeycomb Materials with Electric Conductivity
高木 英典; 松林 和幸; 北川 健太郎; 平岡 奈緒香
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, The University of Tokyo, Grant-in-Aid for Scientific Research (B), 予備的研究では、Materials Informaticsによる効率的物質スクリーニングにより、ハニカム構造Cu3SmTe3を新しい切り口のキタエフ候補物質として見出している。前年度までに、Cu3SmTe3の良質な単結晶育成にも成功した。本年度は、Cu3SmTe3とその置換物質の常圧下基礎物性を決定した。基底状態が反強磁性状態で温度変化に対して二段階の転移を持つこと、キタエフ相互作用を持つことが想定されるΓ7二重項と矛盾しない磁化率温度依存性であることを明らかにした。また、TeのAsへの置換によって、キャリア(ホール)ドープした多結晶体を得ることに成功している。一方で、常圧の物性開発では期待されるエキゾチックな状態の発現には至っていない。Cu3SmTe3とその置換体では確かに半金属性と何らかのフラストレート磁性を両立できているが、伝導を担うキャリアとSm磁性イオンとのカップリングが弱く、電荷ドーピングにより磁性を制御するまでには至っていない。今後は、超10GPaの非常に高い圧力を印加することで、さらに探索のスペースを広げる。 キタエフ型相互作用の存在が示唆された別の物質、CrSiTe3では前年度に高圧強磁性(半)金属相と圧力誘起超伝導相の共存または相分離を発見し、強磁性の飽和磁気モーメントの短縮が何らかのフラストレーションに関係している可能性を見出してきた。今年度により詳細に調べた結果、共存する圧力誘起超伝導相のバルク性については否定的な結論を得つつある。今後は、この非自明な強磁性相と超伝導相の問題を決着させる。 両物質、および他の候補物質では磁性相制御と状態観測に超高圧下での精密磁化測定が有効である。本年度は、これまで開発に注力してきた7 GPa程度までのセルを改良し、超10GPaを再現性良く発生できる見込みがたった。本技術により新奇な量子磁性相開拓を遂行する。, 23K22451
01 Apr. 2022 - 31 Mar. 2025 - Development of Kitaev Honeycomb Materials with Electric Conductivity
高木 英典; 北川 健太郎; 松林 和幸; 平岡 奈緒香
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, The University of Tokyo, Grant-in-Aid for Scientific Research (B), 22H01180
01 Apr. 2022 - 31 Mar. 2025 - High-pressure study of novel quantum phases via thermal properties
Kazuyuki Matsubayashi
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, The University of Electro-Communications, Grant-in-Aid for Scientific Research (C), In condensed matter physics, high pressure is widely used as a powerful tool to search for new physical properties and to elucidate their electronic states. In this study, we have developed and improved experimental methods of thermal properties under pressure, aiming to explore novel quantum phases due to spin, orbital and valence instabilities. Systematic studies under high pressure tuning have successfully revealed intriguing features common to prototypical materials exhibiting unconventional quantum critical phenomena. Furthermore, new routes to improve the properties of thermoelectric materials containing rare earth elements have been obtained., 21K03442
01 Apr. 2021 - 31 Mar. 2024 - Toward realization of honeycomb-structure quantum liquid and study of excitations
Kitagawa Kentaro
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, The University of Tokyo, Grant-in-Aid for Scientific Research (B), The key study of quantum spin physics like Kitaev spin liquid should be verification of the exotic excitations. The pseudo 1/2 spin systems, d5 honeycomb compounds, have been believed to be best suited for such the study. But, candidate materials lack varieties and easy to dimerize upon pressure, and sometimes full of deficiencies. We applied broader approach: Lanthanoids and utilization of high pressures. We developed a highly sensitive technique to conduct magnetometry under very high pressures up to 7 GPa using an opposed-anvil type cell, which can detect a weak paramagnetic susceptibility. We acquired signatures of Kitaev physics in a Pr compound, found a new Kitaev candidate material in a Sm compound, and discovered a good model case as quasi-2D Bose-Einstein condensation of Bosons in a Yb compound., 19H01836
01 Apr. 2019 - 31 Mar. 2022 - 高圧力制御による励起子凝縮と超伝導の研究
松林和幸
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, The University of Electro-Communications, Grant-in-Aid for Scientific Research (B), Principal investigator, We have constructed a comprehensive pressure-temperature phase diagram of the excitonic insulator Ta2NiSe5. In particular, a partial gap involving electron-lattice interaction appears in the high-pressure semimetallic phase, and superconductivity emerges around a critical pressure where the collapse of the gap is observed. We have also discovered pressure-induced superconductivity in BiS2-based layered compounds located near the semiconductor-semimetal transition and observed the similar phase diagram for Ta2NiSe5., 18H01172
01 Apr. 2018 - 31 Mar. 2021 - 高圧力で拓く多極子と伝導電子の混成効果による新奇物性
松林和幸
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, The University of Electro-Communications, Grant-in-Aid for Scientific Research on Innovative Areas (Research in a proposed research area), Principal investigator, 本課題では，多極子自由度が関与した多彩な相転移や伝導現象に着目し、特に四極子自由度が関与した近藤効果や超伝導を高圧下での精密物性測定によって明らかにすることを目的とした。特に、高圧下での熱力学的な特性を明らかにすべく，比熱および熱電能測定法の開発に取り組んだ。四極子自由度を有するPr系化合物PrTi2Al20に対しては、約9 GPaまでの高圧力下での比熱を半定量的に評価し、重い電子超伝導の発現による比熱異常を観測すること成功した。また、高圧下比熱測定での測温技術を応用することで、高圧下・磁場中での熱電能測定法を3 GPa程度の圧力域まで確立することにも成功した。さらに高圧下・磁場中電気抵抗測定からは、PrTi2Al20の四極子秩序が消失する10 GPaを超えた領域の幅広い圧力・磁場領域において、四極子近藤効果を示唆する非フェルミ液体的挙動が観測されることを見出した。四極子自由度を有する新たなPr系化合物として、Znを含む1-2-20系物質のZnサイトの一部をSnで置換したPrRu2Sn2Zn18に対する研究も行った。その結果、常圧では約2 Kで四極子秩序を示す一方で、加圧により混成効果が顕著な増大を示すことを見出した。これと類似した圧力効果は、PrTi2Al20においても観測されており、Al系とZn系物質の物性を統一的に理解するための重要な手がかりになると期待される。さらに、常圧において四極子秩序とキャント磁性を示すBa2MgReO6の単結晶試料における圧力効果の研究も行った。その結果，理論的に予言されていた八極子および新奇な磁性相の存在を示唆する多彩な圧力-温度相図を実験的に得ることを成功した。本課題から得られた成果は、多極子自由度を有する系に対する新奇物性の開拓につながると期待される。, 18H04312
01 Apr. 2018 - 31 Mar. 2020 - 軌道自由度に起因する量子相転移と新奇超伝導の高圧下物性研究
Matsubayashi Kazuyuki
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, The University of Electro-Communications, Grant-in-Aid for Scientific Research (C), PrT2Al20 (T=Ti,V) with non-magnetic doublet ground state provides the unique opportunity to study the strong hybridization effect between the ground doublet and conduction electrons, which gives rise to the quadrupolar Kondo effect as well as superconductivity. In this study, we have investigated the effect of pressure on PrT2Al20 (T=Ti,V) and constructed the detail phase diagrams to shed light on the interplay between the quadrupole order and superconductivity. In both compounds, applying pressure suppresses the quadrupole order and a dome-like superconducting phase emerges. We also found that the anomalous metallic state emerges in wide pressure and field range, as predicted for the quadrupole Kondo lattice model., 15K05161
01 Apr. 2015 - 31 Mar. 2018 - 相転移近傍で現れる新奇超伝導現象の研究
上床美也
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, The University of Tokyo, Grant-in-Aid for Scientific Research (B), In this study, we have investigated the origin of superconductivity on the pressure induced superconductors and looked for the new novel physical properties under pressure. The pressure phase diagram of pressure induced superconducting materials were submitted and suggested the origin of its superconductivity. In addition, we found out a few kinds new pressure induced superconducting materials., 15H03681
01 Apr. 2015 - 31 Mar. 2018 - 新構造１２４型希土類化合物の開発と超高圧下新量子相の探索
北川健太郎
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, The University of Tokyo, Grant-in-Aid for Challenging Exploratory Research, We have investigated new structure material, which we discovered previously, and ultrahigh-pressure new phenomena for various materials. We have drawn a pressure-temperature phase diagram for a new material YbCo2Ge4, and found that a quantum critical point is located at as low as 1GPa. Next, we focused on Kitaev quantum spin liquid, which has attracted a lot of attention when we started this program. We discovered the first spin liquid material H3LiIr2O6 as a candidate for such a liquid, where it exhibits paramagnetism down to 50mK and peculiar Dirac-like fermionic dispersions. In a cousin hyperhoneycomb-type beta-Li2IrO6 compound, we reported a competition between the magnetic phase and spin-singlet dimer formation under ultrahigh pressures., 15K13523
01 Apr. 2015 - 31 Mar. 2018 - Quantum critical behavior in pressure-induced ferromagnetic systems by tuning pressure and magnetic field
MATSUBAYASHI Kazuyuki
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, The University of Tokyo, Grant-in-Aid for Young Scientists (B), We investigated the pressure-induced valence change and metamagnetic behavior in the vicinity of a magnetic quantum phase transition tuned by pressure and/or magnetic field. We have revealed a characteristic pressure-induced Yb valence crossover within the temperature-pressure phase diagram of YbNi3Ga9 in the vicinity of the magnetic quantum phase transition. Moreover, a first-order metamagnetic transition is found below the critical pressure., 24740220
01 Apr. 2012 - 31 Mar. 2014 - Pressure and magnetic field induced quantum criticality in Yb-based heavy fermion compounds
MATSUBAYASHI Kazuyuki
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, The University of Tokyo, Grant-in-Aid for Young Scientists (B), In recent years, one of the most interesting topics is the ground state properties of heavy fermion metals located at or close to a quantum critical point(QCP). To obtain the new insights on the quantum critical behavior in Yb-based heavy fermion systems under pressure and magnetic field, we have developed new type of high pressure cell. Combined pressure-and magnetic-field-tuned specific heat measurements reveal a novel phase diagram in YbCo_2Zn_<20>. We also found the pressure-induced ferromagnetic order in YbNi_3Ga_9., 22740217
2010 - 2011 - Investigation of electrical properties under pressure
UWATOKO Yoshiya; MATSUBAYASHI Kazuyuki; MUNAKATA Koji; UMEHARA Izuru; ASO Naofumi; NAKAMURA Toshikazu; SHIGEOKA Toru; FUJIWARA Tetsuya; HEDO Masato
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, The University of Tokyo, Grant-in-Aid for Scientific Research (B), In this investigation, we completed Palm Cubic Anvil High Pressure Cell(PCAC) as a device to perform the physical properties measurements. Magnetization and specific heat have been measured under high magnetic field up to 2 GPa. By using these devices, we clarified physical properties of superconducting phenomena under pressure., 21340092
2009 - 2011 - Single crystal growth of Ce-T-Al(T=transition metals) and development of physical property measurements by GM cryocooler
NISHIOKA Takashi; MATSUMURA Masahiro; KATO Harukazu; SERA Masafumi; TANIDA Hiroshi; SUZUKI Takashi; UWATOKO Yoshiya; MATSUBAYASHI Kazuyuki; KINDO Koichi; KONDO Akihiro; YASUOKA Hiroshi; KAMBE Shinsaku; TOKUNAGA Yo; METOKI Naoto; KANEKO Koji; KODAMA Kazuto; YAMAMOTO Yujio; ISHII Isao; KOBAYASHI Riki; KAWAMURA Yukihiro
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Kochi University, Grant-in-Aid for Scientific Research (C), Magnetic properties of Ce intermetallic compounds have been considered to be understood by Doniach model which describes the competition between Kondo and RKKY interaction. In spite of CeRu_2Al_<10> is located in the non-magnetic ground state regime in which Kondo effect is dominant, a phase transition appears at a temperature as high as 27 K. From the macroscopic and microscopic measurements under multiple extreme condition using high quality single crystals of CeRu_2Al_<10> and the related compounds, we have proposed that this phase transition cannot be described by Doniach model., 21540367
2009 - 2011 - Quantum criticality in Yb-based heavy fermion componds under pressure
MATSUBAYASHI Kazuyuki
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, The University of Tokyo, Grant-in-Aid for Young Scientists (Start-up), 物質の新機能・新物性を探索する手段として圧力・磁場・温度をコントロールパラメーターとした多重極限環境下での物性測定が注目を集めている。最近、圧力を印加することによって磁気秩序が絶対零度において消失する、いわゆる量子臨界点近傍においてエキゾチックな超伝導を示すことが数多く報告されている。しかし、複合極限環境下での物性測定の困難さのため、その本質は解明されていない。本研究では、高圧下においても熱力学的物理量の詳細な温度依存性が観測可能となる装置の開発を行い、イッテルビウム系化合物における磁気量子臨界現象に関わる電子状態の解明をめざした研究を行った。, 19840017
2007 - 2008 - Development of high pressure cell and study of pressure on the strong correlated system
UWATOKO Yoshiya; ISHIMOTO Hidehiko; HEDO Masato; UMEHARA Izuru; SHIGEOKA Toru; MATSUBAYASHI Kazuyuki
Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, The University of Tokyo, Grant-in-Aid for Scientific Research (A), The combination of low temperature, high pressure and magnetic field provides a powerful means to access abroad range of energy scales and thus study physical phenomena such as metal-insulator transitions, pressure induced superconductivity and the evolution of the Fermi surface as a material is driven into the superconducting state. We have been studying to understanding of a new phenomenon to occur under going interplay (and/or competition) between magnetism and superconductivity and pressure induced novel phase transitions etc. A micro high pressure cell and a cubic anvil high pressure cell have been developed ix measurements of specific heat, magnetization and electrical resistivity at low temperature, respectively. This small cell device can be used up to 2 GPa. And, cubic anvil high pressure cell can be used up to 8GPa at 0.57K. We discover that the one-dimensional organic conductor (TMTTF)_2XF_6(X=Sb, As), ZrTe_3 and YbCo_2Zn_20 are pressure induced superconductor; pressure induced reentrant superconductor and pressure induced magnetic compound, respectively., 16204022
2004 - 2007 - 多重極限下における重い電子液体の磁性とボーズ凝縮の研究
松林 和幸
日本学術振興会, 科学研究費助成事業, 名古屋大学, 特別研究員奨励費, 初年度から継続して取り組んできた圧力誘起相転移物質SmSに対して、(i)試料の質と物性との間の相関、(ii)圧力下物性測定方法の開発に着目した研究に取り組むことにより、高圧相におけるintrinsicな物性を引き出すことに成功した。具体的には、MPMS磁化測定装置を用いた高圧下磁化測定方法の開発を高知大学との共同研究により行った。これにより、広い温度・圧力範囲における磁化測定が可能となり、常圧絶縁相から高圧反強磁性的金属相の中間圧力領域において、非磁性基底状態が実現していることを明らかにした。さらに、過去に行われた熱的測定結果から見出されたエネルギーギャップΔとの対応関係から、Δは磁性・非磁性のクロスオーバーを特徴付ける特性温度になっていることを指摘した。これらの実験事実は、30年以上に渡って解決されなかったSmSの高圧相における実験的矛盾を解決するものであり、重要な意義を持つと考えられる。現在のところ、本研究から得られた実験結果をすべて統一的に説明できるモデルはなく、本研究の成果は新しい理論モデルの構築に寄与するものと期待される。 以上の成果は、日本物理学会(2006年秋季大会、年次大会)と京都で開かれた国際会議(ICM)において発表を行った。またさらに3編の論文にまとめられている。, 04J05888
2004 - 2006
