理学博士, 東京大学

neutron scattering

Spin-state Transition

Electric transport

Magnetism

中性子散乱

NMR

スピン転移

電子輸送現象

磁性

Sep. 1994
電気通信大学電気通信学部, 教授

Oct. 1988
電気通信大学電気通信学部, 助教授

Dec. 1980 - Sep. 1988
理化学研究所, 研究員

Apr. 1976
理化学研究所, 研究員補

Apr. 1974 - Mar. 1976
The University of Tokyo, Graduate School, Division of Science, Department of Physics

Apr. 1972 - Mar. 1974
The University of Tokyo, Graduate School, Division of Science, Department of Physics

Apr. 1968 - Mar. 1972
The University of Tokyo, Faculty of Science, Department of Physics

Field-Induced Spin-State Transition in LaCo_1-x_M_x_O_3_ (M = Al, Ga, Rh, and Ir)
K. Sato; A. Matsuo; K. Kindo; Y. Hara; K. Nakaoka; Y. Kobayashi; K. Asai
Journal of the Physical Society of Japan, 日本物理学会, 83, 10, 114712, Oct. 2014, Peer-reviwed, We have investigated the high-field magnetization of lightly doped LaCo1-xMxO3 with M = Al, Ga, Rh, and Ir up to 67 T. The transition field for the field-induced spin-state transition at 4.2 K, which is Bc = 60 T in LaCoO3, increases slightly for M = Al but does not change for M = Ga. On the other hand, the transition field decreases remarkably for M = Rh and Ir. The substitution effect on ®0Hc has been interpreted as arising from the lattice-volume dependence of the excitation energy ¦I of CoI from the low-spin (LS) to high-spin (HS) state. The fraction of CoI is 15% of the total number of Co ions. The remaining Co ions, CoII, are excited from the LS to intermediate-spin (IS) state and contribute to the magnetization at high temperatures above 100K. We propose the coexistence of the HS and IS states in LaCo1-xMxO3. For M = Rh and Ir, Co species with the magnetic ground state, CoIII, are populated by their substitution. The formation mechanism and spin states of CoIII are discussed in comparison with those of the magnetic Co species in La1-xSrxCoO3.
Scientific journal, English

Change in Pr-4f Ground State in Pr_1-x_Y_x_CoO_3_
Y. Kobayashi; Y. Terakado; K. Asai
Journal of the Physical Society of Japan, 日本物理学会, 83, 9, 104704, Sep. 2014, Peer-reviwed, We have investigated the magnetic properties of Pr1␣xYxCoO3. By the introduction of Y at the Pr site, the magnetism of Pr-4 f electrons changes from temperature-dependent Van Vleck paramagnetism with a nonmagnetic 4 f 2 ground state to Curie–Weiss paramagnetism with a magnetic 4 f 1 ground state. As the origin of the change in the magnetic property, the increment of the ligand hole transfer from Co(3d)–O(2p) molecular orbitals into Pr-4 f 2 states by the introduction of Y ions at the Pr sites is discussed, which results from the hybridization between Pr-4 f and Co-3d orbitals via O-2p orbitals.
Scientific journal, English

Magnetic Anomaly of La1-xMxFeO3 (M = Ca, Sr, and Ba) around 100K
Yuki Nakamae; Shu Ishida; Wataru Takemura; Masatoshi Ohno; Akimasa Okada; Toshihiro Mitsui; Yoshihiko Kobayashi; Jin Nakamura; Kichizo Asai
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, PHYSICAL SOC JAPAN, 83, 6, 063701, Jun. 2014, Peer-reviwed, A magnetic anomaly has been found around 100K in La1-xMxFeO3 (M = Ca, Sr, and Ba) and Pr1-xSrxFeO3 with 0.05 <= x <= 0.4; the spontaneous magnetization of the weak ferromagnet increases below about 100K after cooling in a magnetic field. We propose a model in which Fe4+ ions populated by doped holes preferentially occupy one magnetic sublattice of the antiferromagnetic structure in LaFeO3 and PrFeO3 as a result of charge ordering, which induces an inequality between the sublattice magnetizations and modifies the system from the antiferromagnet to a ferrimagnet. The magnetization below the magnetic anomaly temperature is explained as that of a weak ferromagnet with the canted sublattice magnetizations of the ferrimagnet.
Scientific journal, English

Magnetic Properties of the Double Perovskites (Sr1-xLax)(2)CoMO6 with M = Sb, Nb, and Ta
Yoshihiko Kobayashi; Masafumi Kamogawa; Yuuki Terakado; Kichizo Asai
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, PHYSICAL SOC JAPAN, 81, 4, 044708-1~7, Apr. 2012, Peer-reviwed, We have investigated the crystalline structure and the magnetic properties of (Sr1-xLax)(2)CoMO6 with M = Sb, Nb, and Ta. For M = Sb, an almost completely ordered double perovskite structure was realized for all x. On the other hand for M = Nb and Ta, the ionic disorder of Co and M ions occurs for x <= 0.1, while the ionic order increases with increasing Co2+ content resulting from La3+ substitution. The magnetic susceptibility (chi) for M = Sb showed a Curie-Weiss-like temperature dependence for all x values, suggesting the high-spin (HS) or the intermediate-spin (IS) state as the ground state of Co-3d electrons. For M = Nb and Ta with x <= 0.1, the spin state of Co ions is interpreted as a mixture of Co ions with LS and IS (and/or HS) states, and a spin-glass-like freezing of the magnetic Co ions occurs below 20 K. For x >= 0.2, HS or IS states becomes dominant with increasing the ionic order of Co and M. We infer that the difference in the covalent character between M5+-O2- bond for M = Sb and that for M = Nb or Ta is the origin of both the difference of the ionic order and the difference of the spin state of Co ions through the crystalline field around them.
Scientific journal, English

Spin State of Co Ions in Lightly Doped Strontium LaCoO3: Via Study of High-Field Induced Spin State Transition
Keisuke Sato; Akira Matsuo; Koichi Kindo; Yoshihiko Kobayashi; Kichizo Asai
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, PHYSICAL SOC JAPAN, 80, 10, 104702-1~6, Oct. 2011, Peer-reviwed, We have investigated the high field magnetization of La1-xSrxCoO3 for x <= 0.05 up to mu H-0(ext) = 67 T. In a dilute limit, about 30 nonmagnetic Co ions of two species (Co-I and Co-II in LaCoO3) are converted to magnetic Co ions (Co-III) by introducing one Sr2+, leaving the remaining Co-I and Co-II little affected by the Sr doping. This finding shows that a new spin-phase separation with three Co species appears by the Sr doping. The CoIII ions form a magnetic cluster with a net magnetization several times smaller than that expected from the ferromagnetic aligned full moment. A spin-glass freezing appears below T-g = 10 and 18K for x = 0.03 and 0.05, respectively, in a weak magnetic field of 2 mT. In mu(0)Hext >= 10 T, however, the magnetization of Co-III for 0.01 <= x <= 0.05, as a function of temperature and H-ext, is almost independent of x after normalization with the CoIII population. It means that the magnetic correlation among Co-III within the cluster is robust against H-ext, but the magnetic interactions among the clusters, which cause the spin glass transition, are decoupled by H-ext. The origin of the strong magnetic interaction among Co-III in the cluster is considered to arise from the mobile hole within the cluster as proposed in "spin-polaron" model.
Scientific journal, English

Extraordinary Hall effect in Ba1-xSrxRuO3 films
Y. Kobayashi; M. Iwata; T. Kaneko; K. Sato; K. Asai; H. Ohsumi
PHYSICAL REVIEW B, AMER PHYSICAL SOC, 82, 17, 174430-1~6, Nov. 2010, Peer-reviwed, We have investigated the extraordinary Hall effect of Ba1-xSrxRuO3 thin films with x=1 and 0.8. For x=1, the extraordinary Hall resistivity can be interpreted by the skew scattering mechanism in the paramagnetic region above about 160 K. In the ferromagnetic region above about 60 K, the extraordinary Hall coefficient R-s can be expressed by the combination of the skew and the side-jump scattering mechanisms as R-s=a rho+b rho(2) using the electrical resistivity rho, as usually observed in ordinary ferromagnetic metals. Below 60 K, the field dependence of the Hall resistivity rho(H) at intermediate field region cannot be expressed as rho(H)=R0B+RsM, suggesting an additional term in the field dependence of the extraordinary Hall resistivity. R-s below 60 K derived from the high field region does not follow the relation R-s=a rho+b rho(2), suggesting that the coefficients a and b of the skew and the side-jump scattering depends on temperature below 60 K. On the other hand in the sample with x=0.8, no anomalies were observed below 60 K both in temperature and field dependence. According to the structural analysis of the samples, we infer that the modulation of the Fermi surface due to the structural change plays an important roll on the anomaly of the temperature dependence of the extraordinary Hall effect for x=1.
Scientific journal, English

Extraordinary Hall Effect in Ba(1-x)Sr(x)RuO(3)
Y. Kobayashi; M. Iwata; T. Kaneko; K. Sato; K. Asai
INTERNATIONAL CONFERENCE ON MAGNETISM (ICM 2009), IOP PUBLISHING LTD, 200, 012090 1-5, 2010, Peer-reviwed, We have investigated the extraordinary Hall effect of Ba(1-x)Sr(x)RuO(3) thin films with x = 1 and 0.8. For x = 1, the extraordinary Hall coefficient (R(s)) can be interpreted by the skew scattering mechanism in the paramagnetic region (T > 160 K) and by the combination of the skew and the side-jump scattering mechanisms as R(s) = a rho + b rho(2) where rho is the resistivity in the ferromagnetic region above about 60 K. This observation means that the mechanism of the extraordinary Hall effect in the system is basically the same as that of the ordinary ferromagnetic metals. Below 60 K, the extraordinary Hall resistivity rho(H) shows an anomalous field dependence at intermediate field region. R(s) below about 60 K obtained from rho(H)(H) in higher field region shows an anomalous temperature dependence, which suggests that the coefficients a and b of the skew and the side-jump scatterings are temperature and field dependent. No anomalies both in the temperature and the field dependence below 60 K were observed in the sample with x = 0.8. According to the structural analysis of the samples, we infer that the modulation of the Fermi surface due to the structural change plays an important roll on the anomaly of the extraordinary Hall effect for x = 1.
International conference proceedings, English

Magnetic and Transport Properties in Ba(1-x)Sr(x)RuO(3) Single Crystals
Y. Kobayashi; T. Kaneko; K. Asai
INTERNATIONAL CONFERENCE ON MAGNETISM (ICM 2009), IOP PUBLISHING LTD, 200, 012091 1-5, 2010, Peer-reviwed, We have investigated the magnetic and the electrical transport properties in Ba(1-x)Sr(x)RuO(3) single crystals. In BaRuO(3), which has a nine-layer rhombohedral (9R) structure, the magnetic susceptibility has two components; a Curie-Weiss component (chi(cw)) and a Pauli paramagnetic-like one (chi(pp)). chi(pp)(T) increases monotonically with increasing temperature up to 400 K, suggesting an exchange enhanced Pauli paramagnetism by the spin fluctuation. The temperature dependence of the resistivity (rho) shows a minimum around 130 K. In the whole temperature region, the positive magnetoresistance was observed, which cannot be scaled by Kohler rule. The Hall resistivity (rho(H)) is positive and decreases with increasing temperature. In Ba(0.7)Sr(0.3)RuO(3), which has a four-layer hexagonal (4H) structure, the increment of chi(pp)(T) above similar to 100 K and the minimum of rho(T) were not observed, though chi(cw)(T) is almost the same as that of 9R BaRuO(3). The magnetoresistance was negative suggesting the suppression of the spin fluctuation scattering of the conduction electrons. pH is negative at low temperatures, and changes its sign around 100 K. We infer that the difference of the Fermi surface resulting from the different layered-structure yields the distinct magnetic and transport properties.
International conference proceedings, English

^55^Mn NMR in Ferromagnetic Double Perovskites La_1-x_Bi_x_Mn_0.5_Ni_0.5_O_3_
K. Asai; T. Kawakami; S. Enoshita; M. Shiozawa; Y. Kobayashi
Journal of the Physical Society of Japan, 78, 11, 114710-1~5, Nov. 2009, Peer-reviwed
Scientific journal, English

Crystal Structure of Six-Layer Ba_1-x_Sr_x_RuO_3_
Y. Kobayashi; T. Ohishi; T. Kaneko; M. Iwata; K. Asai
Journal of the Physical Society of Japan, 78, 9, 094601-1~5, Sep. 2009, Peer-reviwed
Scientific journal, English

Field Induced Spin-State Transition in LaCoO3
Keisuke Sato; Akira Matsuo; Koichi Kindo; Yoshihiko Kobayashi; Kichizo Asai
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, PHYSICAL SOC JAPAN, 78, 9, 093702-1~4, Sep. 2009, Peer-reviwed, The magnetization of LaCoO3 shows a magnetic transition induced by level crossing at a magnetic field of 60T below 25K, which is consistent with the energy diagram determined from electron spin resonance experiments. However, the amount of Co ions with g = 3.35 contributing to the magnetic transition is sample-dependent and at most 14% of the total Co ions in LaCoO3. We found that the rest of the Co ions also contribute to the magnetization, which is a maximum at around 100 K. We analyzed the magnetization assuming two kinds of Co species, Co-I and Co-II, both of which have the nonmagnetic ground state. The energies and the g values of the magnetic excited states are 135 K and 3.35 for Co-I, and 250-260K and 1.9-2.0 for Co-II, respectively. Co-I ions are suggested to be associated with oxygen vacancies and the surface of LaCoO3.
Scientific journal, English

Significant softening of c(66) and hidden order parameter in the magnetic ordered state of La2-xCaxCoO4 (0.4 <= x <= 0.7)
K. Horigane; T. Kobayashi; M. Suzuki; K. Abe; K. Asai; J. Akimitsu
PHYSICAL REVIEW B, AMER PHYSICAL SOC, 78, 14, 144108-1~6, Oct. 2008, Peer-reviwed, We have measured the longitudinal and transverse sound velocities of La2-xCaxCoO4 (0.4 <= x <= 0.7) propagating along [100], [110], and [001] from 200 K down to 3 K with a frequency of 10 MHz. It was found that c(66) shows a remarkable softening below Co2+ spin-ordering temperature T-N in the whole doping range, while c(11)-c(12)/2 exhibits a clear hardening below Co3+ spin-ordering temperature T-N2 only when x=0.5. To explain the observed anomaly, the Landau free energy for the La2-xCaxCoO4 system has been constructed, including the coupling energy between elastic strains and a two-dimensional order parameter (Q(1),Q(2)), having a spatial modulation along [110] or [<overline>1</overline>10]. We argued that this represents orbital order, and it is this order that leads to the softening of c(66).
Scientific journal, English

Hyperfine magnetic field at Mn-55 in ferromagnetic perovskites REMn0.5(Ni1-xMgx)(0.5)O-3 with RE = La, Pr, Nd, and Eu: RE dependence of supertransferred hyperfine interaction
Takafumi Kawakami; Shumpei Enoshita; Masafumi Kamogawa; Yoshihiko Kobayashi; Kichizo Asai
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, PHYSICAL SOC JAPAN, 77, 9, 094714-1~7, Sep. 2008, Peer-reviwed, The hyperfine magnetic field at Mn-55 in ferromagnetically ordered double perovskites of the form REMn0.5(Ni1-xMgx)(0.5)O-3 with RE = La, Pr, Nd, and Eu were measured by NMR at 1.8 K. The hyperfine Magnetic field which arises from (3d epsilon)(3) unpaired electrons in Mn4+ to which Mn-55 belongs, is -294.5kOe independent of RE species. On the other hand, H-STHF supertransferred from 3d(3z2)-r(2) unpaired electrons in the neighboring Ni2+ ions decreases as RE goes from La (+35.8 kOe) to Eu (+20.1 kOe). The RE dependence arises from the reduction in the covalency of the Mn4+ -O2- and Ni2+-O2- bonds as RE goes from La to Eu, as well as from the cos(2) theta-type bond angle dependence of the STHF interaction. With the RE dependence of covalency determined from H-STHF, the superexchange interaction between Mn4+ and Ni2+ depending on RE in the present system has been well interpreted.
Scientific journal, English

Crystal structure, magnetism, and dielectric properties of La1-xBixNi0.5Mn0.5O3
Yoshihiko Kobayashi; Masanori Shiozawa; Keisuke Sato; Kohji Abe; Kichizo Asai
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, PHYSICAL SOC JAPAN, 77, 8, 084701-1~8, Aug. 2008, Peer-reviwed, We have synthesized the polycrystalline La1-xBixNi0.5Mn0.5O3 for x = 0-0.9 by soft chemical synthesis, and investigated the crystal structure. and the magnetic and the dielectric properties. The crystal has a monoclinic P2(1)/c structure with centrosymmetry for 0 <= x <= 0.7. and has a monoclinic C2 structure with non-centrosymmetry for 0.8 <= x <= 0.9 at room temperature. The ferromagnetic Curie temperature (T-CM) decreases monotonically from 300 K at x = 0 to 150 K at x = 0.9, while the Ni2+- Mn4+ configuration is kept independent of Bi-content. For x >= 0.5. An anomalous increment of the dielectric constant with increasing temperature and the maximum in the dielectric loss accompanied with frequency dispersion were observed around 150 K, which is close to T-CM. However, no evidence showing, ferroelectric ordering was observed below 400 K. For x = 0.7, the increment of the dielectric constant induced by the magnetic field is 7% at T-CM at 9 T. The temperature and the magnetic field dependence of the dielectric properties is discussed based on Maxwell-Wagner model assuming an inhomogeneity of samples and a negative magnetoresistance.
Scientific journal, English

High-field magnetostriction of the spin-state transition compound LaCoO3
Keisuke Sato; Mikhail I. Bartashevich; Tsuneaki Goto; Yoshihiko Kobayashi; Masaru Suzuki; Kichizo Asai; Akira Matsuo; Koichi Kindo
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, PHYSICAL SOC JAPAN, 77, 2, 024601-1~6, Feb. 2008, Peer-reviwed, The transverse and longitudinal magnetostrictions of LaCoO3 have been measured in pulsed magnetic fields of up to 35 T in the temperature range between 4.2 and 300 K. The magnetostrictions are proportional to the squared magnetic field of up to B-0 = 25 T. The magnetostrictions at B < B-0 are analyzed with a spin-state transition model involving a nonmagnetic ground state and a magnetic excited state for Co ions where Co ions in the latter have a larger optimum lattice volume than those in the former. The observed magnetostrictions are well interpreted by the excited state with g = 3.35 and the excitation energy of A = 140 K, which are consistent with those obtained in an electron spin resonance study [Noguchi et al.: Phys. Rev. B 66 (2002) 0944041 but do not reproduce the observed magnetization. The analysis based on the model and a comparison of the present data to the pressure dependence of the magnetization suggest that the elastic energy represented in terms of only the lattice volume is insufficient for the quantitative description of magnetoelastic phenomena in LaCoO3. A sharp increase in the longitudinal magnetostriction with a large hysteresis observed in B > B-0 and T > 60 K is ascribed to a change in the domain structure of the twinned LaCoO3 crystal induced by a magnetic field.
Scientific journal, English

Epitaxial Growth of Fe_3_Si Thin Films on (100) Magnesia Substrates
Kensuke Akiyama; Satoru Kaneko; Teiko Kadowaki; Yasuo Hirabayashi; Azusa Kyoduka; Yutaka Sawada; Yoshihiko Kobayashi; Kichizo Asai; Hiroshi Funakubo
Mater. Res. Soc. Symp. Proc., 1032E, I14-10, Nov. 2007, Peer-reviwed
International conference proceedings, English

Structural characterization by electronic transport properties on Fe3Si films
Y. Kobayashi; T. Kaneko; M. Kamogawa; K. Asai; K. Akiyama; H. Funakubo
JOURNAL OF PHYSICS D-APPLIED PHYSICS, IOP PUBLISHING LTD, 40, 22, 6873-6878, Nov. 2007, Peer-reviwed, We have investigated the electronic transport properties of resistivity, magnetoresistance and the Hall effect on epitaxial and polycrystalline Fe3Si thin films. The electrical transport measurements reveal the microstructure which has not been clarified from x-ray diffraction and/or scanning electron microscopy. We show that (100)-oriented epitaxial film 36 nm thick on MgO(111) exhibits ferromagnetic-tunnelling conduction, (110)-oriented epitaxial film 36 nm thick on yttria stabilized zirconia [YSZ(111)] is in a percolated region, and polycrystalline film 36 nm thick on Al2O3(110) and (100)-oriented epitaxial film 150 nm thick on MgAl2O4(100) have metallic conduction. These results imply that the electrical transport measurements are a powerful tool for evaluating the microstructure of the samples. The coefficients of the skew and the side-jump scatterings in the extraordinary Hall effect, and the quadratic temperature coefficient of resistivity observed on (100)-oriented epitaxial film 150 nm thick on MgAl2O4 show that Fe3Si is a ferromagnetic metal where the effective electron mass is slightly enhanced compared with Fe, Co and Ni due to the electron-electron correlation.
Scientific journal, English

Electronic structure of-La1-xPrxCoO3 and NdCoO3 studied by photoemission spectroscopy
T. Saitoh; D. Ishii; A. Hachimura; M. Hirose; Thant Sin Naing; Y. Kobayashi; K. Asai; M. Nakatake; M. Higashiguchi; K. Shimada; H. Namatame; M. Taniguchi
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS, ELSEVIER SCIENCE BV, 310, 2, 981-983, Mar. 2007, Peer-reviwed, We have investigated the electronic structure of La1-xPrxCoO3 and NdCoO3 studied by photoemission spectroscopy at 200 K using several photon energies over the Pr or Nd 4d-4f resonance. All the spectra except near the 4d-4f on-resonance displayed a distinct sharp peak at similar to 1 eV due to the Co 3d(6) low-spin (LS) and/or intermediate-spin (IS) state. This 1-eV peak in PrCoO3 and NdCoO3 was substantially narrower than that of LaCoO3, indicating that the IS-LS mixed state is realized in LaCoO3 at 200 K while the pure LS state persists in the others. We point out that the line shape of the Pr 4f partial density of states (PDOS) of PrCoO3, extracted from the on- and off-resonance spectra, was quite different from that of PrMnO3 but rather similar to that of PrBa2Cu3O7. (c) 2006 Elsevier B.V. All rights reserved.
Scientific journal, English

Structural Analysis of Iron Mixed-Valence Complex (n-C_3_H_7_)_4_N[Fe^II^Fe^III^(dto)_3_] (dto = C_2_O_2_S_2_) under High Pressure
M. Itoi; N. Kida; C. Lin; M. Koeda; N. Kojima; M. Hedo; Y. Uwatoko; Y. Kobayashi; K. Asai; Y. Ohishi; M. Takata
J. Phys. Soc. Jpn., 76, Suppl. A, 190-191, 2007, Peer-reviwed
International conference proceedings, English

Nuclear quadrupole relaxation of Ce-140 implanted in highly oriented pyrolytic graphite
W. Sato; H. Ueno; A. Taniguchi; Y. Itsuki; Y. Kasamatsu; A. Shinohara; K. Asahi; K. Asai; Y. Ohkubo
PHYSICAL REVIEW B, AMER PHYSICAL SOC, 74, 21, Dec. 2006, Peer-reviwed, Nuclear quadrupole relaxation was observed for extremely dilute Ce-140 ions implanted in highly oriented pyrolytic graphite by means of the time-differential perturbed angular correlation technique. The temperature-dependent relaxation of the directional anisotropy implies a thermally activated motion of the probe nuclei relative to the extranuclear field with the activation energy of 0.029(3) eV. As regards the electronic property, it is strongly suggested from a measurement under an external magnetic field that the 140Ce ions in motion are in the state of Ce3+.
Scientific journal, English

Spin-State Transition in La_1-x_Pr_x_CoO_3_
Y. Kobayashi; T. Mogi; K. Asai
Journal of the Physical Society of Japan, The Physical Society of Japan (JPS), 75, 10, 104703-104703-6, Oct. 2006, Peer-reviwed, We have investigated the crystalline structure and the magnetic properties of La1-xPrxCoO3 single crystals. The crystalline symmetry is rhombohedral $R\bar{3}c$ for $0 \le x \le 0.3$, and orthorhombic $P_{nma}$ for $0.7 \le x \le 1$. The lattice volume decreases monotonically with increasing Pr content due to the smaller ionic radius of Pr3+ than La3+. The temperature dependence of the magnetic susceptibility [$\chi(T)$] arising from Co3+ ions in La1-xPrxCoO3 was evaluated using La1-xPrxAlO3 as a reference. The temperature dependence of the effective magnetic moment arising from Co ions is interpreted by the three spin-states low-spin (LS), intermediate-spin (IS) and high-spin (HS). The energy of the IS-state ($\Delta_{1}$) increases with increasing Pr content through the chemical pressure. The chemical pressure dependence of $\Delta_{1}$ agrees with the hydrostatic pressure dependence. In contrast to the first spin-state transition, the second spin-state transition is almost independent of the Pr content.
Scientific journal, English

Ultrasonic measurement of LaCoO3 - Evidence for the orbital-order fluctuation
Thant Sin Naing; Toshiaki Kobayashi; Yoshihiko Kobayashi; Masaru Suzuki; Kichizo Asai
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, PHYSICAL SOC JAPAN, 75, 8, 084601(1-8), Aug. 2006, Peer-reviwed, The sound velocity propagating along [111] of LaCoO3 has been measured from 4 to 580 K for longitudinal (L) and transverse (T) sounds with frequencies, f, of 10 to 100 MHz. A comparison of the data for the single-domain rhombohedral crystal with those for a twinned pseudocubic specimen reveals the anisotropy of the elastic constants with the rhombohedral symmetry. The temperature dependence of the velocity of the L mode with f = 10 MHz is analyzed consistently with the anomalous lattice expansion associated with the spin state transition. A frequency dispersion of the sound velocity appears in the L mode above 100K. The amplitude of the dispersion increases pronouncedly with increasing temperature up to the measured highest temperature. The relaxation rate of the lattice evaluated based on the Debye model shows an activation type of temperature dependence with an attempt frequency of (1/tau)(0) = 187 x 10(6) s(-1) and the energy E-a = 11 meV. The slow lattice relaxation is attributed to a fluctuation of the orbital-order of Co atoms in the intermediate spin state and also to the relaxation between the intermediate- and the high-spin states, the rate of which is slowed down to that of the orbital fluctuation.
Scientific journal, English

Uniaxial pressure effect on RENi2B2C (RE = Ho and Y)
Yoshihiko Kobayashi; M. Iwata; T. Okamoto; H. Takeya; K. Kuroki; M. Suzuki; K. Asai
PHYSICA B-CONDENSED MATTER, ELSEVIER SCIENCE BV, 378-80, 475-476, May 2006, Peer-reviwed, We have investigated the uniaxial pressure (P) effect on RENi2B2C for RE = Ho and Y. On HoNi2B2C2. the antiferromagnetic (AF) transition temperature remarkably increases with applying P parallel to [110], suggesting that the stress along [110] stabilizes the AF ordering through the enhancement of the magnetic anisotropy of Ho moments. On the other hand, a pressure dependence of the superconducting transition temperature was not observed. The finding of the present experiment suggests that the AF interaction has no influence on the origin of the superconductivity in this system. (c) 2006 Elsevier B.V. All rights reserved.
Scientific journal, English

Neutron scattering study of phonons in LaCoO3
Y Kobayashi; TS Naing; M Suzuki; M Akimitsu; K Asai; K Yamada; J Akimitsu; P Manuel; JM Tranquada; G Shirane
PHYSICA B-CONDENSED MATTER, ELSEVIER SCIENCE BV, 378-80, 532-533, May 2006, Peer-reviwed, We have investigated phonons with the inelastic neutron scattering in order to study the 100 K spin-state transition (ST) in LaCoO3 The acoustic phonon dispersions show some characteristic features of the folded Brillouin zone (BZ) of the rhombohedrally distorted perovskite structure containing two chemical formula of LaCoO3 in the unit cell. The optical phonons of the E, rotational modes of 0 atoms and the E. vibration mode of La atoms show a remarkable softening above the ST. The softening is most pronounced at R-point of the pseudo-cubic reciprocal lattice but covers almost whole region of the Brillouin zone. In contrast, the acoustic phonons show no such softening associated with the ST. (c) 2006 Elsevier B.V. All rights reserved.
Scientific journal, English

Inelastic neutron scattering study of phonons and magnetic excitations in LaCoO3
Y Kobayashi; TS Naing; M Suzuki; M Akimitsu; K Asai; K Yamada; J Akimitsu; P Manuel; JM Tranquada; G Shirane
PHYSICAL REVIEW B, AMERICAN PHYSICAL SOC, 72, 17, 174405, Nov. 2005, Peer-reviwed, We have investigated the phonon and the magnetic excitations in LaCoO3 by inelastic neutron scattering measurements. The acoustic phonon dispersions show some characteristic features of the folded Brillouin zone (BZ) for the rhombohedrally distorted perovskite structure containing two chemical formula units of LaCoO3 in the unit cell. We observed two transverse optical (TO) phonon branches along (delta delta delta), consistent with previously reported Raman active E-g modes which show remarkable softening associated with the spin-state transition [Ishikawa , Phys. Rev. Lett. 93, 136401 (2004)]. We found that the softening takes place in the TO mode over the whole BZ. In contrast, the acoustic phonons show no anomalous softening associated with the spin-state transition. The low-energy paramagnetic scattering at 8 K is weak, increasing towards a maximum at E greater than or similar to 15 meV, consistent with excitation of the nonmagnetic low-spin to magnetic intermediate-spin state of Co3+ ions.
Scientific journal, English

Mn-55 NMR in ferromagnetic perovskites RENi0.5Mn0.5O3 (RE = rare earth element)
K Asai; N Kobayashi; T Bairo; N Kaneko; Y Kobayashi; M Suzuki; Y Satoh; M Mizoguchi
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, PHYSICAL SOC JAPAN, 74, 4, 1289-1296, Apr. 2005, Peer-reviwed, The hyperfine magnetic fields, H-HF, at Mn-55 were measured by NMR at 2 K for ferromagnetically ordered double perovskites REMn0.5Ni0.5O3 (RE = rare earth element). The field HHF tends to decrease as RE goes from La (-258 kOe) to Lu (-282 kOe). In addition to the overall RE dependence a break is found between RE = Tb and Dy. The field H-HF is interpreted as the sum of H-HF,H-Mn4+ arising from the unpaired electrons in Mn4+ to which Mn-55 belongs and H-STHF supertransferred from the neighboring Ni2+ ions. The present result shows that H-STHF decreases by 30-55%, as RE goes from La to Lu, due to the reduction of the covalency of Ni2+-O2- and Mn4+-O2- bonds, in addition to a 25% decrease arising from the cos(2) theta-type bond angle dependence of H-STHF. The reduction of the covalency as RE goes from La to heavier elements reasonably explains the non-linear cos(2) theta dependence of T-C of the present oxides. The magnetic moments of RE ions do not contribute to the "average" H-HF. but give rise to large transverse relaxation rates by their fluctuation, which is suppressed by an applied magnetic field.
Scientific journal, English

Crystal structure and structural transition caused by charge-transfer phase transition for iron mixed-valence complex (n-C3H7)(4)N[ (FeFeIII)-Fe-II(dto)(3)] (dto = C2O2S2)
M Itoi; A Taira; M Enomoto; N Matsushita; N Kojima; Y Kobayashi; K Asai; K Koyama; T Nakano; Y Uwatoko; J Yamaura
SOLID STATE COMMUNICATIONS, PERGAMON-ELSEVIER SCIENCE LTD, 130, 6, 415-420, May 2004, Peer-reviwed, (n-C3H7)(4)N[ (FeFeIII)-Fe-II(dto)(3)] shows a new type of first order phase transition called chare-transfer phase transition around 120 K. where the charge transfer between Fe-II and Fe-III occurs reversibly. Recently, we have succeeded in obtaining single crystals of the title complex and determined the crystal Structure at room temperature. Crystal data: space group P6(3), a = 10.0618(5) Angstrom. c = 16.0424(7) Angstrom. V = 1406.54(12)Angstrom, Z = 2. Moreover. we have investigated the structural transition caused by the charge-transfer phase transition by means of powder X-ray diffraction measurement. When the temperature is decreased. the a-axis. which corresponds to the hexagonal ring size in two-dimensional honeycomb network structure of [Fe-II Fe-III(dto)(3)](infinity). contracts by 0.1 Angstrom at the charge-transfer transition temperature (T-CT) while the c-axis. perpendicular to the honeycomb network layer. elongates by 0.1 Angstrom at T-CT. Consequently, when the temperature is decreased, the unit cell volume decreases without noticeable anomaly around T-CT, which is responsible for the quite sniall vibrational contribution to the entropy change. compared with usual spin crossover transition. Thus, the charge-transfer phase transition around 120 K for (n-C3H7)(4)N[Fe-II Fe-III(dto)(3)] is regarded as spin entropy driven phase transition. (C) 2004 Elsevier Ltd. All rights reserved.
Scientific journal, English

Magnetic and transport properties in La1-xPrxCoO3 single crystals
Y Kobayashi; T Nakajima; K Asai
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS, ELSEVIER SCIENCE BV, 272, 83-84, May 2004, Peer-reviwed, We have investigated the magnetic and electronic transport properties in the single crystals of La1-xPrxCoO3 System. The signs of the thermoelectric power and the Hall coefficient change from positive to negative by the 10% Pr-doping in LaCoO3, and they change from negative to positive by 10% La-doping in PrCoO3. These results imply that the sign of the carrier of the system changes through the hybridization between Pr(4f) and O(2p(n)) orbitals depending on the Pr concentration. (C) 2004 Published by Elsevier B.V.
Scientific journal, English

Pressure-induced charge-transfer phase transition in a mixed-valence iron complex
Y Kobayashi; M Itoh; K Kojima; K Asai
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS, ELSEVIER SCIENCE BV, 272, 1091-1092, May 2004, Peer-reviwed, We have investigated the hydrostatic pressure effect on the charge-transfer (CT) phase transition in (n-C5H11)(4)N[ (FeFeIII)-Fe-II (dto)(3)]. The system shows a pressure-induced CT phase transition. The CT phase transition appears discontinuously at around the pressure P = 0.5 GPa and the transition temperature increases linearly with increasing the pressure above 0.5 GPa. The present investigation reveals that the CT phase transition of the system is a phenomenon where the spin and the charge states are strongly correlated with the lattice. (C) 2004 Elsevier B.V. All rights reserved.
Scientific journal, English

Eleastic constants of HoNi_2_B_2_C
M. Suzuki; T. Kimura; M. Suetake; Y. Takahashi; K. Asai; S. Isida; H. Takeya
Journal of Magnetism and Magnetic Materials, 272-276, E467-E468, 2004, Peer-reviwed
Scientific journal, English

Ultrasonic study on superconducting HoNi2B2C and Ho0.75Y0.25Ni2B2C
M Suetake; Y Takahashi; M Suzuki; K Abe; K Asai; K Kuroki; S Isida; H Takeya
PHYSICA B-CONDENSED MATTER, ELSEVIER SCIENCE BV, 329, 2, 539-540, May 2003, Peer-reviwed, We performed ultrasonic measurements for HoNi2B2C and Ho0.75Y0.25Ni2B2C single crystals between 1.7 and 80 K under various magnetic field. In zero field, C-66 for HoNi2B2C decreases continuously on lowering temperature in a wide temperature region below 80 K, and showed a discontinuous softening and recovering at 5.5 and 3.8 K, respectively. In contrast, (C-11-C-12)/2 remained almost constant in the whole temperature region. In the field applied along the b(a)-axis, the softening Of C-66 was largely suppressed, which suggests that the softening is magnetic in origin. A similar softening Of C-66 was also observed for Ho0.75Y0.25Ni2B2C. (C) 2003 Elsevier Science B.V. All rights reserved.
Scientific journal, English

Pressure effect on charge-transfer phase transition in a mixed-valence iron complex, (n-C3H7)(4)N[ (FeFeIII)-Fe-II(dto)(3)] (dto = C2O2S2)
Y Kobayashi; M Itoi; N Kojima; K Asai
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, PHYSICAL SOC JAPAN, 71, 12, 3016-3020, Dec. 2002, Peer-reviwed, We have investigated the hydrostatic pressure effect on the charge-transfer phase transition between Fe-II and Fe-III in a mixed-valence iron complex, (eta-C3H7)(4)N[ (FeFeIII)-Fe-II(dto)(3)] (dto = C2O2S2) up to 0.9 GPa. The transition temperature of the char.-e-transfer phase transition increases almost linearly with increasing applied hydrostatic pressure (similar to100 K/GPa), while the ferromagnetic Curie temperature (T-c similar to 7 K) changes only slightly. The results suggest that the applied hydrostatic pressure stabilizes the low-temperature phase [Fe-II(S = 0)-Fe-III(S = 5/2)] through the compression of the lattice volume. A phenomenological model taking into account the elastic interactions as a molecular-field explains the characteristics of the charge-transfer phase transition. The analysis of the results of the model calculation suggests that the lattice volume of the high-temperature phase is only about 0.2% larger than that of the low-temperature phase, and a lattice deformation of [ (FeFeIII)-Fe-II(dto)(3)] molecules without the lattice expansion plays an important role in the first-order character of the charge-transfer phase transition.
Scientific journal, English

Magnetic, electronic transport, and calorimetric investigations of La1-xCaxCoO3 in comparison with La1-xSrxCoO3
K Muta; Y Kobayashi; K Asai
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, PHYSICAL SOC JAPAN, 71, 11, 2784-2791, Nov. 2002, Peer-reviwed, The magnetic and electronic transport proper-ties and the specific heat of La1-xCaCoO3 (0.05 less than or equal to x less than or equal to 0.5) have been investigated. In the whole composition range, the Co atoms are in an intermediate-spin (IS) state, and a spin glass or a ferromagnetic ordered state appears at low temperatures. The conductivity increases with x, and shows a metallic temperature dependence for x greater than or equal to 0.4. The overall resemblance of the Ca substituted system with the Sr substituted one implies that the Ca substitution introduces holes into Co-O bonds as in the case of the Sr substitution. The present results reveal that the hole-doping, not the ionic size, is essential to stabilize the IS state of Co atoms in La1-xMxCoO3 with M being a divalent ion. The quantitative difference, lower T-C and less conductivity for M = Ca than M = Sr with the same x, suggests less mobility and/or less number of holes in the system with M Ca. The electronic specific heat coefficient, null for LaCoO3, increases sharply around x = 0.2 for M Sr and x = 0.25 for M = Ca, and saturates at higher concentrations. The observation indicates the presence of the Fermi surface in the deeply substituted specimens. The magneto-tran sport properties of the metallic specimens, especially a large amplitude of the side-jump scattering in the extraordinary Hall resistivity, are characteristic of itinerant ferromagnetic metals, which supports the double exchange mechanism in the present system.
Scientific journal, English

Anomalous Hall effect in La1-xCaxCoO3
SA Baily; MB Salamon; Y Kobayashi; K Asai
APPLIED PHYSICS LETTERS, AMER INST PHYSICS, 80, 17, 3138-3140, Apr. 2002, Peer-reviwed, La1-xCaxCoO3 films show the largest anomalous Hall effect of any ferromagnetic metal. The anomalous Hall coefficient increases as x decreases. At doping below 0.2 La1-xCaxCoO3 is insulating and shows spin-glass behavior at low temperature. We have measured the Hall effect and magnetic behavior of an x=0.15 crystal. It shows cluster-glass or correlated-spin-glass behavior at intermediate temperatures. The anomalous Hall effect does not depend on the total magnetization, M, but on the ferromagnetic correlations of the glass. (C) 2002 American Institute of Physics.
Scientific journal, English

Pressure effect on ferromagnetic transition and charge-transfer phase transition in a mixed-valence iron complex (n-C_3_H_7_)_4_N[FeFeIII)-FeII(dto)_3_] (dto=C_2_O_2_S/2/)
M. Itoi; N. Kojima; Y. Kobayashi; K. Asai
Molecular Crystals and Liquid Crystals, 379, 2002, Peer-reviwed
Scientific journal, English

Hall effect and thermoelectric power correlated with the giant magnetoresistance in modified FeRh compounds
Y. Kobayashi; K. Muta; K. Asai
J. Phys.: Condens. Matter., 13, 14, 3335-3346, Apr. 2001, Peer-reviwed
Scientific journal, English

Dynamic and electronic properties of a Ce@C_80_: Comparative studies by the time-differential perturbed angular correlation technique with ^140^Ce（←^140^La）probes in graphite and diamond
W. Sato; K. Sueki; Y. Achiba; H. Nakahara; Y. Ohkubo; K. Asai
Phys. Rev. B, 63, 2, 024405-1 - 024405-11, Jan. 2001, Peer-reviwed
Scientific journal, English

Resonance photoemission of LaCoO3(111) and La0.9Sr0.1CoO3(111)
AG Thomas; WR Flavell; PM Dunwoody; CEJ Mitchell; S Warren; SC Grice; PGD Marr; DE Jewitt; N Khan; VR Dhanak; D Teehan; EA Seddon; K Asai; Y Koboyashi; N Yamada
JOURNAL OF PHYSICS-CONDENSED MATTER, IOP PUBLISHING LTD, 12, 44, 9259-9279, Nov. 2000, Peer-reviwed, Resonant photoemission performed at the SRS Daresbury Laboratory is used to investigate the temperature- and doping-dependent spin states in single crystal LaCoO3(111) and La0.9Sr0.1CoO3(111). In an initial study, the surface reactivity of the LaCoO3(111) surface is investigated using H2O as a probe molecule. The results are used to interpret changes which may occur in the spectra as a function of time and temperature in UHV, due to surface reactions. This allows us to distinguish effects on the valence band spectra due to spin changes as a function of temperature. The temperature dependence of low binding energy features primarily associated with Co in the low spin (LS) state in LaCoO3 is investigated in detail. In particular, the intensity and onset energy of the Co 3p -> 3d resonance associated with these features is measured at small binding energy intervals. Delayed resonance onset associated with the LS state is consistently observed. This is used to locate the separate contributions of the low spin and higher spin states to the low binding energy spectrum. We find the contribution due to the LS state lies around 1 eV to lower binding energy than that due to higher spin states in LaCoO3. In contrast, we find the spectrum of La0.9Sr0.1CoO3(111) to be invariant with temperature, with no delayed resonance effect. The data are discussed in the light of recent models for the spin transitions, including the two stage spin-state model involving an intermediate spin state. Simulation of the temperature variation of the valence band spectra of LaCoO3 using this model provides good agreement with experiment.
Scientific journal, English

Structural phase transition from rhombohedral to cubic in LaCoO3
Y Kobayashi; T Mitsunaga; G Fujinawa; T Arii; M Suetake; K Asai; J Harada
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, PHYSICAL SOC JAPAN, 69, 10, 3468-3469, Oct. 2000, Peer-reviwed
Scientific journal, English

Nuclear-spin relaxation of^59^Co correlated with the spin-state transitions in LaCoO_3_
Y. Kobayashi; N. Fujiwara; S. Murata; K. Asai; H. Yasuoka
Phys. Rev. B, 62, 1, 410-415, Jul. 2000, Peer-reviwed
Scientific journal, English

NMR study of the spin-state transitions in LaCoO3
Y Kobayashi; N Fujiwara; S Murata; K Asai; H Yasuoka
PHYSICA B, ELSEVIER SCIENCE BV, 281, 512-513, Jun. 2000, Peer-reviwed, A study of Co-59-NMR on single crystals of LaCoO3 is presented in order to investigate the spin-state transition through the nuclear-spin relaxation. The spin-lattice and spin-spin relaxation rates exhibit a thermal activation-type temperature dependence at low temperatures, suggesting the spin-singlet ground state with a spin gap. The magnitude of the gap energy similar to 180 K is close to the values predicted by the two-stage spin-state model including the intermediate spin state, supporting the propriety of the model. (C) 2000 Elsevier Science B.V. All rights reserved.
Scientific journal, English

Magnetic and Transport Properties of LaCo_1-x_Ni_x_O_3_ -Comparison with La_1-x_Sr_x_CoO_3_
Y. Kobayashi; S. Murata; K. Asai; J. M. Tranquada; G. Shirane; K. Kohn
Journal of the Physical Society of Japan, 68, 3, 1011-1017, Mar. 1999, Peer-reviwed
Scientific journal, English

Elastic anomalies with the spin-state transitions in LaCoO3
S Murata; S Isida; M Suzuki; Y Kobayashi; K Asai; K Kohn
PHYSICA B, ELSEVIER SCIENCE BV, 263, 647-649, Mar. 1999, Peer-reviwed, Ultrasonic measurements of LaCoO3 were performed from 4.2 to 600 K. We observed two lattice softenings related to the spin-state transitions of LaCoO3 around 100 and 500 K. The temperature dependence of the elastic modulus is well explained by a model involving three spin states coupled with the lattice. The parameters obtained from the present ultrasonic measurement are in good agreement with those previously obtained from lattice expansion. (C) 1999 Elsevier Science B.V. All rights reserved.
Scientific journal, English

Electronic state of Ce@C-82
W Sato; K Sueki; K Kikuchi; K Kobayashi; S Suzuki; Y Achiba; H Nakahara; Y Ohkubo; F Ambe; K Asai
JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY, SPRINGER, 239, 1, 187-190, Jan. 1999, Peer-reviwed, Time-differential perturbed angular correlation method was applied to Ce@C-82 in order to investigate the electronic properties of the encaged Ce atom. The nuclear quadrupole frequency of the nuclear spin of the Ce was successfully determined as omega(Q) = 6.5(3)(.)10(7) rad/s, which is much greater than what has already been estimated for Ce4+ and La3+ in other compounds. By comparing the present value with the values for the Ce4+ and La3+, it was inferred that the valence state of the encaged Ce atom is trivalent.
Scientific journal, English

Electronic structure and surface reactivity of La1-xSrxCoO3
WR Flavell; AG Thomas; J Hollingworth; S Warren; SC Grice; PM Dunwoody; CEJ Mitchell; PGD Marr; D Teehan; S Downes; EA Seddon; S Downes; EA Seddon; VR Dhanak; K Asai; Y Koboyashi; N Yamada
FARADAY DISCUSSIONS, ROYAL SOC CHEMISTRY, 114, 407-420, 1999, Peer-reviwed, Resonant photoemission performed at the SRS Daresbury is used to investigate the temperature- and doping-dependent spin transitions in single crystal samples of the La1-xSrxCoO3 system (x = 0, x = 0.1). For LaCoO3, the measurements taken over a wide temperature range are interpreted in the light of current models for the spin transitions. The Sr-doped compound is found to be in the same spin state at all temperatures. The temperature dependence of low binding energy features primarily associated with Co in the low spin state is investigated in detail. In particular, the intensity and onset energy of the Co3p --> 3d resonance associated with these features is measured at small binding energy intervals. This is used to locate the separate contributions of the low spin and higher spin states to these signals. In addition, the surface reactivity of the LaCoO3 (111) surface is investigated using H2O as a probe molecule, and the results are used to interpret changes which may occur in the spectra as a function of time in UHV.
Scientific journal, English

Dynamic Motion of Ce@C_80_ - Comparison Study with Ce@C_82_
W. Sato; K. Sueki; K. Kikuchi; S. Suzuki; Y. Achiba; H. Nakamura; Y. Ohkubo; K. Asai; F. Ambe
AIP Conference Proceedings, 486, 120-123, 1999, Peer-reviwed
International conference proceedings, English

Magnetic properties of REMe0.5Mn0.5O3 (RE = rare earth element, Me = Ni, Co)
K Asai; K Fujiyoshi; N Nishimori; Y Satoh; Y Kobayashi; M Mizoguchi
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, PHYSICAL SOC JAPAN, 67, 12, 4218-4228, Dec. 1998, Peer-reviwed, Magnetic properties of REMe0.5Mn0.5O3 with Me = Ni and Co are investigated for a series of rare earth (RE) elements. In both systems with Me Ni and Co. the Curie temperature (Tc), below which the magnetic moments of Me2+ and Mn4+ allign ferromagnetically, decreases remarkably as RE goes from La to heavier elements; from 295 Ii for RE = La tu 50 It for Lu with Me = Ni, and from 250 K for La to 95 It for Ho with Me Co. The decrease of T-C is interpreted as due to the bond angle (theta) dependence of the superexchange interactions between Me2+ and Mn4+ through O2-; TC is roughly linear to cos(2)theta as predicted Ly a simple theory [C. Boekema ct al.: Int. J. Mag. 3 (1972) 341], but a distinct deviation from the linear relation is observed for the late RE elements. The magnetic moments of RE ions appears only in a low temperature region, typically below 30 K. Qualitative discussion on the exchange interactions involving RE is presented.
Scientific journal, English

Molecular and intramolecular dynamics of a C-80 dimetallofullerene
W Sato; K Sueki; K Kikuchi; S Suzuki; Y Achiba; H Nakahara; Y Ohkubo; K Asai; F Ambe
PHYSICAL REVIEW B, AMER PHYSICAL SOC, 58, 16, 10850-10856, Oct. 1998, Peer-reviwed, Molecular and intramolecular dynamics of solid-state CeLa@C-80 has been studied based on time-differential perturbed-angular-correlation (TDPAC) measurements by employing the Ce-140 nucleus, a beta(-) decay product of La-140, as the probe. Rotational motion of the molecules was suggested by the temperature dependence of the reorientational correlation time of electric quadrupole interaction tau(c), which abruptly changes at approximately 160 K, implying the freezing of the motion. The dynamic motion of the Ce atom was observed even below that temperature, down to 40 K, and all of the motions causing dynamic perturbation on the nucleus vanish at further low temperatures. Some intrinsic nature of the interactions among and within the fullerene molecules, CeLa@C-80, is also discussed in comparison with Ce@C-82, based on physical parameters obtained by the TDPAC method. [S0163-1829(98)09639-8].
Scientific journal, English

ペロブスカイト型強磁性酸化物RENi_0.5_Mn_0.5_O_3_の^55^MnのNMR
場色正昭; 金子直樹; 西森宣彦; 小林義彦; 浅井吉蔵; 溝口森二
日本物理学会秋の分科会（沖縄）講演概要集, 53, 2, 第3分冊、535, Sep. 1998
Japanese

γ-γ摂動角相関法による金属内包フラーレンの動的挙動の研究
佐藤 渉; 末木啓介; 菊地耕一; 鈴木信三; 阿智波洋次; 中原弘道; 大久保嘉高; 浅井吉蔵; 安部文敏
日本物理学会秋の分科会（沖縄）講演概要集, 53, 2, 第2分冊、320, Sep. 1998
Japanese

Novel Dynamic Behavior of Ce@C_82_ at Low Temperature
W. Sato; K. Sueki; K. Kikuchi; K. Kobayashi; S. Suzuki; Y. Achiba; H. Nakahara; Y. Ohkubo; F. Ambe; K. Asai
Phys. Rev. Lett., 80, 1, 133-136, Jan. 1998, Peer-reviwed
Scientific journal, English

Two Spin-State Transitions in LaCoO_3_
K. Asai; A. Yoneda; O. Yokokura; J. M. Tranquada; G. Shirane; K. Kohn
J. Phys. Soc. Jpn., 67, 1, 290-296, Jan. 1998, Peer-reviwed
Scientific journal, English

Time-Differential Perturbed-Angular-Correlation Studies on ^117^In and ^111^Cd in Li_0.99_Cd_0.005_NbO_3_
Y. Ohkubo; S. Uehara; Y. Kawase; J. Nakamura; T. Okada; S. Ambe; F. Ambe; K. Asai
Phys. Rev. B, 56, 17, 10730-10733, Nov. 1997, Peer-reviwed
Scientific journal, English

Pressure Dependence of the 100 K Spin-State Transition in LaCoO_3_
K. Asai; O. Yokokura; M. Suzuki; T. Naka; T. Matsumoto; H. Takahashi; N. Mori; K. Kohn
J. Phys. Soc. Jpn., 66, 4, 967-970, Apr. 1997, Peer-reviwed
Scientific journal, English

Studies on Structural Phase Transition of Barium-Ruthenium Metal Oxides by ^117^In TDPAC
Y. Yanagida; J. Nakamura; K. Asai; N. Yamada; Y. Ohkubo; S. Ambe; T. Okada; F. Ambe; S. Uehara; Y. Kawase
Hyperfine Interactions(c), 1, 412-415, 1996, Peer-reviwed
Scientific journal, English

^57^Fe Mossbauer Spectroscopy of Fe_1+x_Sb
J. Nakamura; Y. Kobayashi; K. Asai; N. Yamada; F. Ambe
311-314, 1996, Peer-reviwed
International conference proceedings, English

Structural Phase Transition of BaRu_2/3_M_1/3_O_3_ (M=Ca,Cd, and Sr)Studied by ^117^In (←^117^Cd) Time-Differential Perturbed-Anbular-Correlation
Y. Yanagida; J. Nakamura; K. Asai; N. Yamada; Y. Ohkubo; S. Ambe; T. Okada; F. Ambe; S. Uehara; Y. Kawase
J. Phys. Soc. Jpn., 64, 12, 4739-4747, Dec. 1995, Peer-reviwed
Scientific journal, English

MAGNETIC-PROPERTIES OF (MN(1-X)TE(X))(5)GE-3 - (TE=CR AND FE)
N YAMADA; S SHIBASAKI; K ASAI; Y MORII; S FUNAHASHI
PHYSICA B, ELSEVIER SCIENCE BV, 213, 357-359, Aug. 1995, Peer-reviwed, The site occupancies and the magnetic moments of the transition-metal atoms, TE = Cr and Fe, in the compounds (Mn(1-x)TE(x))(5)Ge-3 have been studied by magnetization and neutron-scattering measurements. Chromium and iron atoms were substituted for the Mn atoms in the compound up to x = 0.3 and 0.2, respectively. In the case of Cr, the magnetization and the Curie temperature decrease with increasing Cr content. The fractions of Cr atoms distributed on the 4d and 6g sites are 60% and 40%, respectively, and their magnetic moments are almost zero at 200 K. In the case of Fe, the magnetization and the Curie temperature increase with increasing Fe content x up to 0.10. The magnetization then decreases with increased Fe content. All the Fe atoms occupy the 4d site. Their magnetic moments at 10 K are + 2.6 +/- 1.1 mu(B), substantially larger than that (1.85 mu(B)) of Mn on the site. The increase in the bulk magnetization on substitution of Fe for Mn is attributed to the large Fe magnetic moment.
Scientific journal, English

Time-Differential Perturbed-Angular-Correlation and Emission Mossbauer Studies on ^99^Ru Dispersed in YBa_2_Cu_3_O_6.8_ and YBa_2_Cu_3_O_6_
Y. Ohkubo; Y. Kobayashi; K. Harasawa; S. Ambe; T. Okada; F. Ambe; K. Asai; S. Shibata
J. Phys. Chem., 99, 26, 10629-10634, Jun. 1995, Peer-reviwed
Scientific journal, English

NMR Study on the Supertransferred Hyperfine Magnetic FieId at ^55^Mn in Ferromagnetic Pervskites La(Co_1-x_Mg_x_)_0.5_Mn_0.5_O_3_
N. Nishimori; K. Asai; M. Mizoguchi
J. Phys. Soc. Jpn., 64, 4, 1326-1333, Apr. 1995, Peer-reviwed
Scientific journal, English

Magnetic Compton Profiles of Ferromagnetic Intermetallic Compound MnSb
J. Nakamura; T. Takeda; K. Asai; N. Yamada; Y. Tanaka; N. Sakai; M. Ito; A. Koizumi; H. Kawata
J. Phys. Soc. Jpn., 64, 4, 1385-1393, Apr. 1995, Peer-reviwed
Scientific journal, English

Local Structure and Valence of Impurity Ions in Oxides by TDPAC and Moessbauer Emission Spectroscopy
F. Ambe; Y. Ohkubo; S. Ambe; Y. Kobayashi; T. Okada; Y. Yanagida; J. Nakamura; K. Asai; Y. Kawase; S. Uehara
Radioanal. and Nucl. Chem., 190, 26, 215-224, Mar. 1995, Peer-reviwed
Scientific journal, English

A Neutron-scattering Study of the Spin-state Transition and Magnetic Correlations in La_1-x_Sr_x_CoO_3_ (x=0 and 0.08)
K. Asai; O. Yokokura; N. Nishimori; H. Chou; J. M. Tranquada; G. Shirane; S. Higuchi; Y. Okajima; K. Kohn
Phys. Rev. B, 50, 5, 3025-3032, Aug. 1994, Peer-reviwed
Scientific journal, English

A Study on Hyperfine Magnetic Field at 117In(←117Cd) in Fe3O4 by γ-γ Time-Differential Perturbed Angular Correlation
Kichizo Asai; Yasuo Yanagida; Shizuko Ambe; Fumitoshi Ambe
Journal of the Physical Society of Japan, 63, 5, 1677-1680, 1994, Peer-reviwed, Hyperfine magnetic fields, Hhf, at 117In arising from 117Cd were measured in Fe3O4 by time-differential perturbed angular correlation (TDPAC) of 90-345 keV y-rays through the intermediate 660 keV state (3/2 +). The values of Hhf were found to be 123 and 138 kOe at 295 and 77 K, respectively. The present work is the frrst one which measured Hhf at 117 In in magnetically ordered materials, and demonstrates the applicability of TDPAC of this nuclide in the field of magnetism. © 1994, THE PHYSICAL SOCIETY OF JAPAN. All rights reserved.
Scientific journal, English

TDPAC and Emission Mossbauer Spectroscopy of ^99^Ru in YBa_2_Cu_3_O_7-y_
Y. Ohkubo; Y. Kobayashi; K. Harasawa; S. Ambe; T. Okada; K. Asai; S. Shibata; M. Takeda; F. Ambe
Hyperfine Interactions, 84, 1-4, 83-86, 1994, Peer-reviwed
Scientific journal, English

MOSSBAUER AND MAGNETIZATION STUDIES ON THE FERROMAGNET FE3-XRUXSI
Y KOBAYASHI; K ASAI; T OKADA; F AMBE
HYPERFINE INTERACTIONS, BALTZER SCI PUBL BV, 84, 1-4, 131-135, 1994, Peer-reviwed, Ru-99 and Fe-57 Mossbauer spectroscopic studies were carried out on ternary intermetallic compounds containing ruthenium, Fe3-xRuxSi, within the concentration range 0.1 less-than-or-equal-to x less-than-or-equal-to 1.5. Magnetization of the samples was also measured in the temperature range between 4 K and room temperature. Ru-99 Mossbauer spectra of x = 0.5 and 1.0 were fitted satisfactorily with a broad component of H(hf), the peak positions of which were 340 and 270 kOe, respectively.
Scientific journal, English

Hyperfine Interactions of ^121^Sb in a Magnetic Chalcogen Spinel CuCr_2-x_Sb_x_S_4_
J. Nakamura; T. Okada; K. Asai; F. Ambe
Nucl. Instrum. and Methods B, 76, 1-4, 39-41, Apr. 1993, Peer-reviwed
Scientific journal, English

^57^Fe Mossbauer Studies of YBa_2_(Cu_1-x_Fe_x_)_4_O_8_
T. Okada; K. Asai; N. Yamada; T. Matsumoto; Y. Yamada; Y. Kodama
Nucl. Instrum. and Methods B, 76, 1-4, 338-340, Apr. 1993, Peer-reviwed
Scientific journal, English

^57^Fe Mossbauer Studies of Bi_2_PbSr_4_Fe_3_O_12_
T. Okada; Y. Kobayashi; K. Asai; N. Yamada; T. Yamadaya
Phase Transitions, 41, 1-4, 255-259, 1993, Peer-reviwed
Scientific journal, English

Time-differential Perturbed-angular-correlation and Emission Mossbauer Studies on ^99^Ru arising from ^99^Rh in Fe_3_O_4_
Y. Ohkubo; Y. Kobayashi; K. Asai; T. Okada; F. Ambe
Phys. Rev. B, 47, 18, 11954-11961, 1993, Peer-reviwed
Scientific journal, English

TDAPC and Emission Mossbauer Studies of Fe_3_O_4_(^99^Ru)
Y. Ohkubo; Y. Kobayashi; K. Asai; T. Okada; F. Ambe
Hyperfine Interactions, 78, 1-4, 535-539, 1993, Peer-reviwed
Scientific journal, English

^57^Fe Mossbauer Studies of poly- and single crystals YBa_2_Cu_3-X_Fe_X_O_7-Y_
T. Okada; K. Asai
Riken Review, 2, 21-22, 1993, Peer-reviwed
Research institution, English

Magnetization Measurement and ^55^Mn NMR Study of La(Ni_1-x_Mg_x_)_0.5_Mn_0.5_O_3_
M. Sonobe; K. Asai
J. Phys. Soc. Jpn., 61, 11, 4193-4203, Nov. 1992, Peer-reviwed
Scientific journal, English

^99^Ru(←^99^Rh) as a TDPAC Probe in the Study of a High-Tc Superconductor
Y. Ohkubo; Y. Kobayashi; S. Ambe; K. Harasawa; M. Takeda; S. Shibata; K. Asai; T. Okada; F. Ambe
Chemistry Letters, 10, 2069-2072, Oct. 1992, Peer-reviwed
Scientific journal, English

Mossbauer Spectroscopy and Magnetization Studies on α-and β-RuCl_3_
Y. Kobayashi; T. Okada; K. Asai; M. Katada; H. Sano; F. Ambe
Inorganic Chemistry, 31, 22, 4570-4574, Oct. 1992, Peer-reviwed
Scientific journal, English

SYNTHESIS AND CHARACTERIZATION OF A NEW MU-ALKOXODIIRON(III) COMPLEX WITH NO5 DONOR SET ENVIRONMENTS
S KAWATA; M NAKAMURA; Y YAMASHITA; K ASAI; K KIKUCHI; IKEMOTO, I; M KATADA; H SANO
CHEMISTRY LETTERS, CHEMICAL SOC JAPAN, 1, 135-138, Jan. 1992, Peer-reviwed, A new dinuclear iron(III) complex, [Fe2(hpta) (Obz) (H2O)2], where H5hpta is 2-hydroxy-1,3-propanediamine-N,N,N',N'-tetraacetic acid and HObz is benzoic acid, was prepared and characterized. X-Ray structure analysis revealed that the complex has mono-(mu-carboxylato) (mu-alkoxo) diiron(III) core and each iron atom has an NO5 donor set in a distorted octahedron.
Scientific journal, English

Mossbauer Emission Spectroscopy of ^57^Fe Arising from ^57^Mn in Metal and Oxides of Chromium
M. Nakada; Y. Yatanabe; K. Endo; H. Nakahara; H. Sano; K. Mishima; M. K. Kubo; Y. Sakai; T. Tomonaga; K. Asai; M. Iwamoto; Y. Kobayashi; T. Okada; N. Sakai, I
Bull. Chem. Soc. Jpn., 65, 1, 1-5, Jan. 1992, Peer-reviwed
Scientific journal, English

Mossbauer Studies of Single Crystal YBa_2_Cu_3-x_Fe_x_O_7-y_
T. Okada; M. D. Lan; J. Z. Liu; R. N. Shelton; T. Matsumoto; K. Asai
Physica C, 185, 2, 783-784, Dec. 1991, Peer-reviwed
Scientific journal, English

^57^Fe Mossbauer Studies of BiPbSr_2_FeO_6_
T. Okada; Y. Kobayashi; K. Asai; N. Yamada; T. Yamadaya
Physica C, 185, 2, 1125-1126, Dec. 1991, Peer-reviwed
Scientific journal, English

Europium-151 Mossbauer Effect Study of Europium Orthovanadite
J. S. Zheng; Y. Kobayashi; J. Nakamura; K. Asai; G. L. Zhang; F. Ambe
Hyperfine Interactions, 68, 1-4, 307-310, 1991, Peer-reviwed
Scientific journal, English

SB-121 MOSSBAUER-SPECTROSCOPY OF MN1+XSB
J NAKAMURA; Y KOBAYASHI; F AMBE; K ASAI; N YAMADA
HYPERFINE INTERACTIONS, BALTZER SCI PUBL BV, 68, 1-4, 311-314, 1991, Peer-reviwed, Sb-121 Mossbauer spectra for ferromagnets, Mn1+xSb (0.00 less-than-or-equal-to x less-than-or-equal-to 0.22) in epsilon-phase were measured at 77 K. The large unique hyperfine magnetic field (H(hf) = 361 kOc) at x = 0 tends to decrease and to have a wide distribution with increase of x. The decreasing ratio of the mean value of H(hf) for the nonstoichiometric samples is in accordance with that of their magnetization M(S)(x), i.e., the relation H(hf)BAR(x)/H(hf)(0) = M(S)(x)/M(S)(0) holds in this system.
Scientific journal, English

Pressure-induced Structural and Magnetic Phase Transitions in CeZn
T. Shigeoka; Y. Uwatoko; H. Fujii; L. Rebelsky; S. M. Shapiro; K. Asai
Phys. Rev. B, 42, 13, 8394-8398, Nov. 1990, Peer-reviwed
Scientific journal, English

MAGNETIC HYSTERESIS BEHAVIOR OF ANISOTROPIC SPIN-GLASS FE2TIO5
JK SRIVASTAVA; J HAMMANN; K ASAI; K KATSUMATA
PHYSICS LETTERS A, ELSEVIER SCIENCE BV, 149, 9, 485-487, Oct. 1990, Peer-reviwed
Scientific journal, English

MAGNETIC HYSTERESIS BEHAVIOR OF ANISOTROPIC SPIN-GLASS FEMNTIO5
JK SRIVASTAVA; K ASAI; K KATSUMATA
PHYSICA B, ELSEVIER SCIENCE BV, 165, 1, 181-182, Aug. 1990, Peer-reviwed
Scientific journal, English

^99^Ru, ^61^Ni, ^57^Fe Mossbauer Studies of Heusler Alloys Containing Ruthenium
Y. Kobayashi; T. Okada; M. Iwamoto; F. Ambe; M. Katada; H. Sano; K. Asai
Hyperfine Interactions, 54, 1-4, 585-590, Jul. 1990, Peer-reviwed
Scientific journal, English

Time-differential Perturbed-angular-correlation Study of Hyperfine Interactions at ^111^Cd(←^111^In)in α-Fe_2_O_3_
K. Asai; F. Ambe; S. Ambe; T. Okada; H. Sekizawa
Phys. Rev. B, 41, 10, 6124-6136, Apr. 1990, Peer-reviwed
Scientific journal, English

TEMPERATURE-INDUCED MAGNETISM IN LACOO3
K ASAI; P GEHRING; H CHOU; G SHIRANE
PHYSICAL REVIEW B, AMERICAN PHYSICAL SOC, 40, 16, 10982-10985, Dec. 1989, Peer-reviwed
Scientific journal, English

^99^Ru, ^57^Fe Mossbauer Spectroscopy of a Ruthenium Alloy, RuFe_2_Si
Y. Kobayashi; M. Katada; H. Sano; T. Okada; K. Asai; F. Ambe
J. Radioanal. Nucl. Chem. Letters, 136, 5, 387-394, 1989, Peer-reviwed
Scientific journal, English

Mossbauer Studies on Heusler Alloy
Y. Kobayashi; M. Katada; H. Sano; K. Asai; T. Okada; M. Iwamoto; F. Ambe
Proc. of the Int. Symp. on Advanced Nucl. Energy Res., 412-413, 1989, Peer-reviwed
Research society, English

TIME-DIFFERENTIAL PERTURBED-ANGULAR-CORRELATION STUDY OF HYPERFINE INTERACTIONS AT CD-111 IN A LI0.5FE2.5O4 SINGLE-CRYSTAL
K ASAI; T OKADA; T YAMADAYA; H SEKIZAWA
PHYSICAL REVIEW B, AMERICAN PHYSICAL SOC, 37, 16, 9140-9147, Jun. 1988, Peer-reviwed
Scientific journal, English

Mossbauer Spectroscopic Studies of Ruthenium Trichlorides
Y. Kobayashi; M. Katada; H. Sano; T. Okada; K. Asai; N. Sakai; S. Ambe; F. Ambe
Hyperfine Interactions, 40, 487-490, 1988, Peer-reviwed
Scientific journal, English

^57^Fe Mossbauer Study on YBa_2_Cu_3-x_Fe_x_O_7_
T. Okada; N. Sakai; K. Asai; Y. Toba; T. Yamadaya
Hyperfine Interactions, 42, 1231-1234, 1988, Peer-reviwed
Scientific journal, English

TDPAC Studies of the After-effects of ^111^In→^111^Cd EC Decay in a-Fe_2_O_3_ and Other Inorganic Compounds
K. Asai; F. Ambe; S. Ambe; T. Okada; H. Sekizawa
Radiochimica Acta., 43, 64, 1988, Peer-reviwed
Scientific journal, English

AN INVESTIGATION ON THE AFTEREFFECTS OF IN-111(-]CD-111) EC DECAY IN ALPHA-FE2O3
K ASAI; F AMBE; S AMBE; T OKADA; H SEKIZAWA
HYPERFINE INTERACTIONS, BALTZER SCI PUBL BV, 34, 1-4, 277-280, Apr. 1987, Peer-reviwed
Scientific journal, English

SUPERTRANSFERRED HYPERFINE MAGNETIC-FIELDS AT CD-111([-IN-111) IN FERRIMAGNETIC OXIDES WITH THE SPINEL STRUCTURE
K ASAI; T OKADA; H SEKIZAWA
HYPERFINE INTERACTIONS, BALTZER SCI PUBL BV, 34, 1-4, 435-438, Apr. 1987, Peer-reviwed
Scientific journal, English

COMPARATIVE MOSSBAUER AND TDPAC STUDIES ON THE AFTEREFFECTS OF THE EC DECAYS OF SB-119 AND IN-111 IN ALPHA-FE2O3
F AMBE; K ASAI; S AMBE; T OKADA; H SEKIZAWA
HYPERFINE INTERACTIONS, BALTZER SCI PUBL BV, 29, 1-4, 1197-1200, Feb. 1986, Peer-reviwed
Scientific journal, English

TDPAC of γ-Rays Emitted from ^111^Cd(←^111^In) in Fe_3_O_4_
K. Asai; T. Okada; H. Sekizawa
Journal of Physical Society of Japan, 54, 11, 4325-4330, 1985, Peer-reviwed
Scientific journal, English

TDPAC of g-rays Emitted from 111Cd(←111In) in Magnetic Oxides
K. Asai; T. Okada; F. Ambe; S. Ambe; H. Sekizawa
2, 400-402, 1985, Peer-reviwed
English

TDPAC of γ-Rays Emitted from ^111^Cd(←^111^In) in α-Fe_2_O_3_
K. Asai; F. Ambe; S. Ambe; H. Sekizawa
J. Phys. Soc. Jpn., 53, 4109-4112, 1984, Peer-reviwed
Scientific journal, English

Magnetization Measurements and ^57^Fe Mossbauer Studies of LaNi_1-x_Fe_x_O_3_ (0.0≦x≦]0.2)
K. Asai; H. Sekizawa
Journal of Physical Society of Japan, 49, 1, 90-98, 1980, Peer-reviwed
Scientific journal, English

Mossbauer Study of ^57^Fe in LaNi_1-x_Fe_x_O_3_ (0≦X≦0.2)
K. Asai; H. Sekizawa
Journal de Physique, 40, 3, C2-255-C2-257, 1979, Peer-reviwed
Scientific journal, English

Impurity Levels of Iron-Group Ions in TiO_2_
K. Mizushima; M. Tanaka; K. Asai; S. Iida; J. B. Goodenough
J. Phys. Chem. Solids, 40, 1129-1140, 1979, Peer-reviwed
Scientific journal, English

Magnetization Measurements and ^55^Mn NMR Studies of LaNi_0.5_Mn_0.5_O_3_
K. Asai; H. Sekizawa; S. Iida
J. Phys. Soc. Jpn., 47, 1054-1060, 1979, Peer-reviwed
Scientific journal, English

Magnetic Properties of LaNi_1-x_Fe_x_O_3_ (0≦X≦0.2)
K. Asai; H. Sekizawa; K. Mizushima; S. Iida
J. Phys. Soc. Jpn., 45, 1417-1418, 1978, Peer-reviwed
Scientific journal, English

Magnetic Properties of LaNi_1-x_Co_x_O_3_ (0≦x≦0.5)
K. Asai; H. Sekizawa; K. Mizushima; S. Iida
Journal of Physical Society of Japan, 43, 3, 1093-1094, 1977, Peer-reviwed
Scientific journal, English

Crystal structure and Magnetic Properties of MnSeO_3_, CoSeO_3_, NiSeO_3_, and CuSeO_3_
K. Kohn; S. Akimoto; K. Inoue; K. Asai; O. Horie
J. Phys. Soc. Jpn., 38, 587, 1975, Peer-reviwed
Scientific journal, English

Crystal structure and Magnetic Properties of MnTeO_3_, CoTeO_3_ and NiTeO_3_
K. Kohn; S. Akimoto; Y. Uesu; K. Asai
J. Phys. Soc. Jpn., 37, 1169, 1974, Peer-reviwed
Scientific journal, English

One Electron Energy Levels of Iron Impurities in TiO_2_
K. Mizushima; M. Tanaka; K. Asai; S. Iida
AIP Conference Proceedings, 18, 1044-1048, 1974, Peer-reviwed
Scientific journal, English

ペロブスカイト型Co酸化物のスピンクロスオーバー現象：その歴史と現状
浅井吉蔵; 小林義彦; 佐藤桂輔
ペロブスカイト型Co酸化物のスピンクロスオーバー現象は50年の歴史を持つが、未だ未解決の問題を残している。何が問題を複雑にしているかを明らかにするために、研究の歴史と現状を紹介する。, 日本物理学会, 05 Jan. 2015, 日本物理学会誌, 70, 1, 6-13, Japanese, Peer-reviwed, Invited, Introduction other, 0029-0181, 110009900502, AN00196952

TDPAC of ^117^In(←^117^Cd) : A potent nuclear probe for magnetic materials
K. Asai; Y. Ohkubo; Y. Yanagida; J. Nakamura; T. Okada; S. Ambe; S. Uehara; Y. Kawase; F. Ambe
1997, RIKEN Review, 16, 9-10, English, Peer-reviwed, Introduction other

TDPAC and emission Mossbauer studies on ^99^Ru in YBa_2_Cu_3_O_6.8_ and YBa_2_Cu_3_O6
Y. Ohkubo; Y. Kobayashi; K. Harasawa; S. Ambe; T. Okada; K. Asai; S. Shibata; F. Ambe
1997, RIKEN Review, 16, 11-12, English, Peer-reviwed, Introduction other

Studies on structural phase transition of barium-ruthemium-metal oxides by ^117^In-TDPAC
Y. Ohkubo; Y. Yanagida; J. Nakamura; K. Asai; N. Yamada; S. Ambe; T. Okada; S. Uehara; Y. Kawase; F. Ambe
1997, RIKEN Review, 16, 13-14, English, Peer-reviwed, Introduction other

TDPAC of ^117^In and ^111^Cd in Li_0.995_Cd_0.005_NbO_3_
Y. Ohkubo; S. Uehara; Y. Kawase; J. Nakamura; T. Okada; S. Ambe; K. Asai; F. Ambe
1997, RIKEN Review, 16, 15-16, English, Peer-reviwed, Introduction other

Molecular and intramolecular dynamics of metallofullerenes investigated by time-differential perturbed angular correlation
W. Sato; K. Sueki; K. Kikuchi; K. Kobayashi; S. Suzuki; Y. Achiba; Y. Ohkubo; F. Ambe; K. Asai; H. Nakahara
1997, RIKEN Review, 16, 17-18, English, Peer-reviwed, Introduction other

^121^Sb and ^57^Fe Mossbauer spectroscopy of MnM_x_Sb(M=Mn and Fe)
J. Nakamura; Y. Kobayashi; K. Asai; N. Yamada; F. Ambe
1997, RIKEN Review, 16, 31-32, English, Peer-reviwed, Introduction other

γ-γ摂動角相関による物性研究
浅井吉蔵
Jun. 1993, RADIOISOTOPES、日本アイソトープ協会, 42, 6, 347-364, Japanese, Introduction other

ペロブスカイト型酸化物 LaNi_1-x_M_x_O_3_ (M=Fe, Co) 及び LaNi_0.5_Mn_0.5_O_3_ の磁性
浅井吉蔵; 関澤尚
1981, 固体物理, 16, 379-389, Japanese, Introduction other

γーγ摂動角相関
浅井吉蔵; 関澤尚
1980, 化学総説 ー核現象と分析化学ー, 29, 81-97, Japanese, Introduction other

LaCo_1-x_Te_x_O_3_における強磁場誘起スピン転移
市川拓; 佐藤桂輔; 松尾晶; 金道浩一; 原嘉昭; 中岡鑑一郎; 小林義彦; 浅井吉蔵
Poster presentation, Japanese, 日本物理学会2014年秋期大会/日本物理学会講演概要集, 日本物理学会, 中部大学 春日井キャンパス（愛知県春日井市）, 単結晶La_1-x_Sr_x_CoO_3_ (x=0.2)の応力歪み特性の結晶方位依存性を調べた．, Domestic conference
09 Sep. 2014

スピンクロスオーバー現象の歴史と現状
浅井吉蔵
Nominated symposium, Japanese, 日本物理学会2014年秋期大会/日本物理学会講演概要集, Invited, 日本物理学会, 中部大学 春日井キャンパス（愛知県春日井市）, 単結晶La_1-x_Sr_x_CoO_3_ (x=0.2)の応力歪み特性の結晶方位依存性を調べた．, Domestic conference
09 Sep. 2014

ナノサイズ多結晶La_1-x_Sr_x_CoO_3_ (x=0.2)の磁気特性
大橋優貴; 佐藤桂輔; 原嘉昭; 中岡鑑一郎; 浅井吉蔵; 小林義彦
Poster presentation, Japanese, 日本物理学会2014年秋期大会/日本物理学会講演概要集, 日本物理学会, 中部大学 春日井キャンパス（愛知県春日井市）, ナノサイズ多結晶La_1-x_Sr_x_CoO_3_ (x=0.2)の磁気歪み応答を調べた．, Domestic conference
07 Sep. 2014

単結晶La_1-x_Sr_x_CoO_3_ (x=0.2)の応力歪み特性の結晶方位依存
皆川桂太; 佐藤桂輔; 原嘉昭; 中岡鑑一郎; 浅井吉蔵; 小林義彦
Poster presentation, Japanese, 日本物理学会2014年秋期大会/日本物理学会講演概要集, 日本物理学会, 中部大学 春日井キャンパス（愛知県春日井市）, 単結晶La_1-x_Sr_x_CoO_3_ (x=0.2)の応力歪み特性の結晶方位依存性を調べた．, Domestic conference
07 Sep. 2014

LaCo_1-x_Rh_x_O_3_の電子構造：HX-PESとバンド計算の比較
岡田陸; 田路智也; 大川万里生; 達大樹; 吉田鉄平; 小林義彦; 寺門悠樹; 浅井吉蔵; Xeniya Kozina; 池永英司; 大橋治彦; 山崎裕史; 崎泰久; 坂井延寿; 組頭広志; 浜田典昭; 齋藤智彦
Oral presentation, Japanese, 日本物理学会2014年秋期大会/日本物理学会講演概要集, 日本物理学会, 中部大学 春日井キャンパス（愛知県春日井市）, LaCo_1-x_Rh_x_O_3_の電子構造を明らかにするためにHX-PESとバンド計算の比較を行った。, Domestic conference
07 Sep. 2014

磁化及び超音波測定によるペロブスカイト系Co酸化物のスピン転移の研究
佐藤健; 礒本航; 岩澤貴司; 小林利章; 小林義彦; 中村仁; 浅井吉蔵
Oral presentation, Japanese, 日本物理学会第６９回年次大会/日本物理学会講演概要集, 日本物理学会, 東海大学 湘南キャンパス（神奈川県平塚市）, LaCoO_3_、及び関連物質のスピン転移を磁化測定と超音波測定により研究した。．, Domestic conference
28 Mar. 2014

RE_1-x_M_x_FeO_3_ (RE=La, Pr; M=Sr, Ca, Ba)の100K近傍での磁気異常
竹村航; 石田周; 大野正敏; 三井俊宏; 小林義彦; 中村仁; 浅井吉蔵
Oral presentation, Japanese, 日本物理学会第６９回年次大会/日本物理学会講演概要集, 日本物理学会, 東海大学 湘南キャンパス（神奈川県平塚市）, RE_1-x_M_x_FeO_3_ (RE=La, Pr; M=Sr, Ca, Ba)の100K近傍での磁気異常を明らかにした．, Domestic conference
28 Mar. 2014

La_1-x_Sr_x_FeO_3_の100K付近の磁気異常の単結晶試料による研究
中前雄貴; 岡田晃正; 大野正敏; 小林義彦; 中村仁; 浅井吉蔵
Oral presentation, Japanese, 日本物理学会第６９回年次大会/日本物理学会講演概要集, 日本物理学会, 東海大学 湘南キャンパス（神奈川県平塚市）, La_1-x_Sr_x_FeO_3_の100K付近の磁気異常を単結晶試料により研究した。, Domestic conference
28 Mar. 2014

LaCo_1-x_Rh_x_O_3_の光電子分光
岡田陸; 田路智也; 大川万里生; 和達大樹; 吉田鉄平; 小林義彦; 寺門悠樹; 浅井吉蔵; Xeniya Kozina; 池永英司; 坂井延寿; 組頭広志; 仲武昌史; 生天目博文; 谷口雅樹; 齋藤智彦
Oral presentation, Japanese, 日本物理学会第６９回年次大会/日本物理学会講演概要集, 日本物理学会, 東海大学 湘南キャンパス（神奈川県平塚市）, LaCo_1-x_Rh_x_O_3_のCoスピン状態を光電子分光により研究した．, Domestic conference
28 Mar. 2014

La_1-x_Sr_x_CoO_3_の磁気コンプトン散乱
小林義彦; 佐藤桂輔; 櫻井吉晴; 伊藤真義; 浅井吉蔵
Oral presentation, Japanese, 日本物理学会第６９回年次大会/日本物理学会講演概要集, 日本物理学会, 東海大学 湘南キャンパス（神奈川県平塚市）, 放射光による磁気コンプトン散乱でLa_1-x_Sr_x_CoO_3_中Coのスピン磁気モーメントと軌道磁気モーメントの分離を試みた．, Domestic conference
27 Mar. 2014

Y_3_Fe_5-x_R_x_O_12_ (R = Al, Si, Ga, Ge)中の^57^Fe - NMR
高澤大輔; 大澤明弘; 宮田全展; 中村仁; 溝口森二; 浅井吉蔵
Oral presentation, Japanese, 日本物理学会講演概要集,日本物理学会第６８回年次大会
Mar. 2013

La_1-x_Sr_x_CoO_3_の磁気形状記憶効果
中村麻紀; 佐藤桂輔; 原嘉昭; 中岡鑑一郎; 岩澤貴司; 木原工; 小林義彦; 徳永将史; 浅井吉蔵
Oral presentation, Japanese, 日本物理学会講演概要集,日本物理学会第６８回年次大会
Mar. 2013

Y_1-x_Pr_x_CoO_3_の磁性と電気伝導 II
寺門悠樹; 小薄雅也; 小林義彦; 浅井吉蔵
Oral presentation, Japanese, 日本物理学会講演概要集,日本物理学会第６８回年次大会
Mar. 2013

コンプトン散乱によるLaCoO_3_のスピン転移の研究
小林義彦; 櫻井吉晴; 伊藤真義; 浅井吉蔵
Oral presentation, Japanese, 日本物理学会講演概要集,日本物理学会第６８回年次大会
Mar. 2013

希薄不純物置換LaCoO_3_系の磁場誘起スピン転移
佐藤桂輔; 松尾晶; 金道浩一; 佐藤健; 小林義彦; 浅井吉蔵
Oral presentation, Japanese, 日本物理学会講演概要集,日本物理学会第６８回年次大会
Mar. 2013

Magnetic and electronic transport properties of Y_1-x_Pr_x_CoO_3_
Y. Terakado; Y. Kobayashi; K. Asai
Oral presentation, English, Abstracts of the 2nd International Conference of AUMS/The Asian Union of Magnetics Societies
Oct. 2012

Magnetic and dielectric relaxations in lightly substituted Y_3-x_Ca_x_Fe_5_O_12_ (0<=x<=0.1)
N. Arai; S. Enoshita; S. Ishida; Y. Kobayashi; K. Abe; J. Nakamura; K. Asai
Oral presentation, English, Abstracts of the 2nd International Conference of AUMS/The Asian Union of Magnetics Societies
Oct. 2012

Y_1-x_Pr_x_CoO_3_の磁性と電気伝導
寺門悠樹; 小林義彦; 浅井吉蔵
Oral presentation, Japanese, 日本物理学会講演概要集,日本物理学会2012年秋期大会
Sep. 2012

二重ペロブスカイト型Co酸化物のX線吸収分光
大川万里生; 長谷川敦; 西村淳一; 和田大樹; 田久保耕; 溝川貴司; Tom Z. Regier; 小林義彦; 寺門悠樹; 新井伸英; 浅井吉蔵; 齋藤智彦
Oral presentation, Japanese, 日本物理学会講演概要集,日本物理学会第６７回年次大会
Mar. 2012

単一ドメインLa_1-x_Sr_x_CoO_3_の磁気異方性
中村麻紀; 佐藤桂輔; 原嘉昭; 中岡鑑一郎; 岩澤貴司; 小林義彦; 浅井吉蔵
Oral presentation, Japanese, 日本物理学会講演概要集,日本物理学会第６７回年次大会
Mar. 2012

Y_1-x_Pr_x_CoO_3_の磁性
小林義彦; 寺門悠樹; 浅井吉蔵
Oral presentation, Japanese, 日本物理学会講演概要集,日本物理学会２０１１年秋期大会
Sep. 2011

光電子分光による二重ペロブスカイト型Co酸化物の電子構造
長谷川敦; 西村淳一; 齋藤智彦; 大川万里生; 小林義彦; 寺門悠樹; 新井伸英; 浅井吉蔵; 浜田典明; 仲武昌史; 姜健; 島田賢也; 生天目博文; 谷口雅樹; 上田茂典; 山下良之; 吉川英樹; 小林啓介
Oral presentation, Japanese, 日本物理学会講演概要集,日本物理学会２０１１年秋季大会
Sep. 2011

第７回全国物理コンテスト・物理チャレンジ２０１１実験問題
三沢和彦; 浅井吉蔵; 右近修治; 大嶋孝吉; 岸澤真一; 毛塚博史; 小牧研一郎; 近藤泰洋; 味野道信
Oral presentation, Japanese, 日本物理学会講演概要集,日本物理学会２０１０年秋期大会
Sep. 2011

イットリウム鉄ガーネットの誘電緩和と磁気緩和の試料依存性III
新井伸英; 小林義彦; 阿部浩二; 中村仁; 浅井吉蔵
Oral presentation, Japanese, 日本物理学会講演概要集,日本物理学会第６６回年次大会
Mar. 2011

コア・カリキュラム学習支援システムのハンドブック化
本山美穂; 浅井吉蔵; 阿部浩二; 大槻一雅; 大淵泰司; 奥野剛史; 尾関之泰; 金長正彦; 里岡純子; 島田宏; 清水和子; 鈴木勝; 中村仁; 渡辺信一
Oral presentation, Japanese, 日本物理学会講演概要集,日本物理学会２０１０年秋期大会
Sep. 2010

第４１回国際物理オリンピック・クロアチア大会報告
杉山忠男; 江尻有郷; 毛塚博史; 光岡薫; 向田昌志; 長谷川修司; 興治文子; 中屋敷勉; 真梶克彦; 鈴木亨; 田中忠芳; 山田達之輔; 野添嵩; 田中良樹; 谷崎佑弥; 並木雅俊; 浅井吉蔵; 北原和夫; 原田勲
Oral presentation, Japanese, 日本物理学会講演概要集,日本物理学会２０１０年秋期大会
Sep. 2010

第６回全国物理コンテスト・物理チャレンジ２０１０報告III．実験問題
近藤泰洋; 浅井吉蔵; 右近修治; 岸澤真一; 毛塚博史; 小牧研一郎; 三沢和彦
Oral presentation, Japanese, 日本物理学会講演概要集,日本物理学会２０１０年秋期大会
Sep. 2010

イットリウム鉄ガーネットの誘電緩和と磁気緩和の試料依存性II
新井伸英; 原口数正; 榎下峻平; 小林義彦; 阿部浩二; 中村仁; 浅井吉蔵
Oral presentation, Japanese, 日本物理学会講演概要集,日本物理学会２０１０年秋季大会
Sep. 2010

La_1-x_Eu_x_CoO_3_ (x = 0～1.0) の結晶構造と磁性
内田雅大; 小林義彦; 佐藤博彦; 大石克嘉; 増渕伸一; 浅井吉蔵; 風間重雄
Oral presentation, Japanese, 日本物理学会講演概要集,日本物理学会第６５回年次大会
Mar. 2010

「コア・カリキュラム学習支援」システムの改善手法
金長正彦; 浅井吉蔵; 阿部浩二; 大槻一雅; 大淵泰司; 奥野剛史; 尾関之泰; 島田宏; 清水和子; 鈴木勝; 中村仁; 本山美穂; 渡辺信一
Oral presentation, Japanese, 日本物理学会講演概要集,日本物理学会第６５回年次大会
Mar. 2010

第４１回国際物理オリンピック日本代表訓練研修：実験問題
江尻有郷; 毛塚博史; 光岡薫; 長谷川修司; 浅井吉蔵; 向田昌志; 真梶克彦; 中屋敷勉
Oral presentation, Japanese, 日本物理学会講演概要集,日本物理学会第６５回年次大会
Mar. 2010

学習者カルテに基づくコア・カリキュラムの学習支援とその改善
浅井吉蔵; 阿部浩二; 大槻一雅; 大淵泰司; 奥野剛史; 尾関之康; 金長正彦; 島田宏; 清水和子; 鈴木勝; 中川徹夫; 中村仁; 渡辺信一
Oral presentation, Japanese, 日本物理学会講演概要集,日本物理学会２００９年秋季大会
Sep. 2009

第40回国際物理オリンピック（メキシコ大会）報告
向田昌志; 浅井吉蔵; 江尻有郷; 北原和夫; 毛塚博史; 近藤泰洋; 真梶克彦; 杉山忠男; 鈴木亨; 田中忠芳; 中屋敷勉; 並木雅俊; 長谷川修司; 原田勲; 光岡薫; 山田達之輔
Oral presentation, Japanese, 日本物理学会講演概要集,日本物理学会２００９年秋季大会
Sep. 2009

六層構造Ba_1-x_Sr_x_RuO_3_の構造相転移
小林義彦; 新井伸英; 金子徹也; 浅井吉蔵
Oral presentation, Japanese, 日本物理学会講演概要集,日本物理学会２００９年秋季大会
Sep. 2009

二重ペロブスカイト型Co酸化物の光電子分光
西村淳一; 齋藤智彦; 小林義彦; 浅井吉蔵; 浜田典昭; 仲武昌史; 姜健; 島田賢也; 生天目博文; 谷口雅樹; 上田茂典; 山下良之; 吉川英樹; 小林啓介
Oral presentation, Japanese, 日本物理学会講演概要集,日本物理学会２００９年秋季大会
Sep. 2009

イットリウム鉄ガーネットの誘電緩和と磁気緩和の試料依存性
新井伸英; 榎下峻平; 小林義彦; 阿部浩二; 中村仁; 浅井吉蔵
Oral presentation, Japanese, 日本物理学会講演概要集,日本物理学会２００９年秋季大会
Sep. 2009

La_1-x_Sr_x_CoO_3_における強磁場誘起スピン転移
佐藤桂輔; 松尾晶; 金道浩一; 小林義彦; 浅井吉蔵
Oral presentation, Japanese, 日本物理学会講演概要集,日本物理学会２００９年秋季大会
Sep. 2009

LaCoO_3_における強磁場誘起スピン転移
佐藤桂輔; 松尾晶; 金道浩一; 小林義彦; 浅井吉蔵
Oral presentation, Japanese, 日本物理学会講演概要集,日本物理学会第６４回年次大会
Mar. 2009

La_1-x_Bi_x_Mn_0.5_Ni_0.5_O_3_の^55^Mn NMR
浅井吉蔵; 川上貴史; 榎下俊平; 鴨川征史; 塩沢正規; 小林義彦
Oral presentation, Japanese, 日本物理学会講演概要集,日本物理学会第６４回年次大会
Mar. 2009

国際物理オリンピック２００９教育研修報告
浅井吉蔵; 原田勲; 杉山忠男; 毛塚博史
Oral presentation, Japanese, 日本物理学会講演概要集,日本物理学会第６４回年次大会
Mar. 2009

学習者カルテに基づくコア・カリキュラムの学習支援とその効果
金長正彦; 浅井吉蔵; 阿部浩二; 大槻一雅; 奥野剛史; 尾関之康; 島田宏; 清水和子; 鈴木勝; 中川徹夫; 中村仁; 渡辺信一
Oral presentation, Japanese, 日本物理学会講演概要集,日本物理学会第６４回年次大会
Mar. 2009

ダブルペロブスカイト型強磁性体La_1-x_Bi_x_Mn_0.5_Ni_0.5_O_3_の電気磁気効果と^55^Mn NMR
浅井吉蔵; 小林義彦; 川上貴史; 塩澤正規; 佐藤桂輔; 阿部浩二
Public symposium, Japanese, 「短寿命核および放射線を用いた物性研究（Ｉ）」専門研究会, 京都大学原子炉実験所, 熊取
Nov. 2008

ダブルペロブスカイト型強磁性体La_1-x_Bi_x_Mn_0.5_Ni_0.5_O_3_の電気磁気効果と^55^Mn NMR
浅井吉蔵; 小林義彦; 川上貴史; 塩沢正規; 佐藤桂輔; 阿部浩二
Oral presentation, Japanese, 京都大学原子炉実験所専門研究会報告,京都大学原子炉実験所専門研究会「短寿命核および放射線を用いた物性研究（Ⅰ）
Nov. 2008

層状Ｃｏ酸化物La_2-x_Sr_x_CoO_4_の超音波測定
堀金和正; 小林利章; 鈴木勝; 阿部浩二; 浅井吉蔵; 秋光純
Oral presentation, Japanese, 日本物理学会講演概要集,日本物理学会２００８年秋季大会
Sep. 2008

LaCoO_3_の強磁場物性
佐藤桂輔; 松尾晶; 徳永将史; 金道浩一; 小林義彦; 浅井吉蔵
Oral presentation, Japanese, 日本物理学会講演概要集,日本物理学会２００８年秋季大会
Sep. 2008

(Sr_1-x_La_x_)_2_CoMO_6_ (M=Nb, Ta, Sb)の磁性とスピン状態
鴨川征史; 小林義彦; 浅井吉蔵
Oral presentation, Japanese, 日本物理学会講演概要集/日本物理学会,日本物理学会第６２回年次大会
Sep. 2007

Ba_1-x_Sr_x_RuO_3_の結晶構造と磁性・電子輸送現象
金子徹也; 小林義彦; 浅井吉蔵
Oral presentation, Japanese, 日本物理学会講演概要集/日本物理学会,日本物理学会第６２回年次大会
Sep. 2007

Ba_x_Sr_1-x_RuO_3_の異常ホール効果と磁気構造
小林義彦; 金子徹也; 鴨川征史; 大隅寛幸; 浅井吉蔵
Oral presentation, Japanese, 日本物理学会講演概要集/日本物理学会,日本物理学会第６２回年次大会
Sep. 2007

La_1-x_Bi_x_Mn_0.5_Ni_0.5_0_3_の^55^Mn NMR
川上貴史; 榎下俊平; 鴨川征史; 塩沢正規; 小林義彦; 浅井吉蔵
Oral presentation, Japanese, 日本物理学会講演概要集/日本物理学会,日本物理学会第６１回年次大会
Sep. 2007

X-ray absorption spectroscopy of RECoO_3_ (RE=La, Pr, Nd)
山岸由希; 石井大基; 斉藤智彦; 小林義彦; 浅井吉蔵; 桑原英樹; 三浦雄一; 東口光晴; 島田賢也
Oral presentation, Japanese, The Physical Society of Japan
Sep. 2007

Fe_3_Siの電子輸送現象
金子徹也; 鴨川征史; 小林義彦; 秋山賢介; 舟窪浩; 浅井吉蔵
Oral presentation, Japanese, 日本物理学会講演概要集/日本物理学会,日本物理学会２００７年春季大会
Mar. 2007

La_1-x_Bi_x_Ni_0.5_Mn_0.5_O_3_の磁性と誘電特性
塩澤正規; 佐藤桂輔; 小林義彦; 浅井吉蔵
Oral presentation, Japanese, 日本物理学会講演概要集/日本物理学会,日本物理学会２００７年春季大会
Mar. 2007

(Sr_1-x_La_x_)_2_CoNbO_6_中のCoのスピン状態
鴨川征史; 小林義彦; 浅井吉蔵
Oral presentation, Japanese, 日本物理学会講演概要集/日本物理学会,日本物理学会２００７年春季大会
Mar. 2007

REMn_0.5_(Ni_1-x_Mg_x_)_0.5_0_3_ (RE=La, Pr, Eu)の^55^Mn NMR
川上貴史; 鴨川征史; 小林義彦; 浅井吉蔵
Oral presentation, Japanese, 日本物理学会講演概要集/日本物理学会,日本物理学会第６１回年次大会
Sep. 2006

La_1-x_Bi_x_Ni_0.5_Mn_0.5_O_3_の磁性と誘電特性
塩沢正規; 小林義彦; 阿部浩二; 浅井吉蔵; 佐藤桂輔; 近藤正雄; 丸山研二
Oral presentation, Japanese, 日本物理学会講演概要集/日本物理学会,日本物理学会第６１回年次大会
Mar. 2006

磁性体におけるエンジニアード・ドメイン構造
佐藤桂輔; 小林義彦; 浅井吉蔵; 松尾晶; 金道浩一; 後藤恒明
Oral presentation, Japanese, 日本物理学会講演概要集/日本物理学会,日本物理学会第６１回年次大会
Mar. 2006

SrRuO_3_薄膜の異常ホール効果
小林義彦; 岩田正俊; 浅井吉蔵; 佐藤桂輔; 近藤正雄
Oral presentation, Japanese, 日本物理学会講演概要集/日本物理学会,日本物理学会第６１回年次大会
Mar. 2006

Ba_1-x_Sr_x_RuO_3_の結晶構造
大石鉄治; 村田仁; 岩田正俊; 小林義彦; 浅井吉蔵
Oral presentation, Japanese, 日本物理学会講演概要集/日本物理学会,日本物理学会第６１回年次大会
Mar. 2006

BaRuO_3_薄膜の構造と電子輸送現象
岩田正俊; 小林義彦; 浅井吉蔵; 佐藤桂輔; 近藤正雄
Oral presentation, Japanese, 日本物理学会講演概要集/日本物理学会,日本物理学会第６１回年次大会
Mar. 2006

The relations between electronic states and spin states in cobalt oxides
A. Hachimura; M. Hirose; T. Saitoh; Than Sin Naing; Y. Kobayashi; K. Asai; K. Takubo; J.-Y. Son; T. Mizokawa
Oral presentation, Japanese, The Physical Society of Japan
Sep. 2005

X-ray absorption spectroscopy of RECoO_3_ (RE=La, Pr, Nd)
M. Hirose; A. Hachimura; T. Saitoh; Than Sin Naing; Y. Kobayashi; K. Asai
Oral presentation, Japanese, The Physical Society of Japan
Sep. 2005

Magnetic properties and electric conduction in Y_1-x_Ce_x_CoO_3_
T. Koike; Y. Kobayashi; K. Asai
Oral presentation, Japanese, The Physical Society of Japan
Sep. 2005

光電子分光によるRECoO_3_(RE=Rare Earth)のスピン状態
鉢村敦徳; 石井大基; 斉藤智彦; タンシンナイン; 小林義彦; 浅井吉蔵; 溝川貴司
Oral presentation, Japanese, 日本物理学会講演概要集, 千葉県野田市
Mar. 2005

LaCoO_3_の中性子フォノン散乱
小林義彦; Than Sin Naing; 鈴木勝; 浅井吉蔵; 山田和芳; 秋光正子; 秋光純; P. Manuel; J. M. Tranquada; G. Shirane
Oral presentation, Japanese, 日本物理学会講演概要集, 千葉県野田市
Mar. 2005

超音波測定によるLaCoO_3_のスピン転移の研究（周波数分散）
タンシンナイン; 小林義彦; 鈴木勝; 浅井吉蔵
Oral presentation, Japanese, 日本物理学会講演概要集, 千葉県野田市
Mar. 2005

La_1-x_Pr_x_CoO_3_の構造と磁性
小林義彦; 茂木隆明; 浅井吉蔵
Oral presentation, Japanese, 日本物理学会講演概要集, 千葉県野田市
Mar. 2005

YNi_2_B_2_Cにおける超伝導の一軸圧力効果
小林義彦; 岩田正俊; 鈴木勝; 浅井吉蔵; 竹屋裕幸
Oral presentation, Japanese, 日本物理学会講演概要集, 千葉県野田市
Mar. 2005

強磁性体２重ペロブスカイトRENi_0.5_Mn_0.5_O_3_（RE=希土類元素）中の^55^Mn NMR
浅井吉蔵; 小林憲史; 場色正昭; 金子直樹; 小林義彦; 鈴木勝; 溝口森二
Others, Japanese, Proceedings of the Specialist Research Meeting on New Developments in Solid State Physics with Probes of Radiation and Nuclei, 京都大学原子炉実験所
Nov. 2004

RENi_0.5_Mn_0.5_O_3_（RE=希土類元素）中の^55^Mn NMR (II)
浅井吉蔵; 小林憲史; 小林義彦; 鈴木勝; 溝口森二
Oral presentation, Japanese, 日本物理学会講演概要集, 青森
Sep. 2004

HoNi_2_B_2_Cの磁歪測定
谷口淳子; 小林利章; 鈴木勝; 浅井吉蔵; 竹屋浩幸
Oral presentation, Japanese, 日本物理学会講演概要集, 青森
Sep. 2004

LaCoO_3_のスピン転移によるフォノン異常（中性子散乱）II
小林義彦; Thant Sin Naing; 鈴木勝; 浅井吉蔵; 山田和芳; 秋光正子; 秋光純; P. Manuel; J. M. Tranquada; G. Shirane
Oral presentation, Japanese, 日本物理学会講演概要集, 青森
Sep. 2004

LaCoO_3_のスピン転移によるフォノン異常
小林義彦; Thant Sin Naing; 鈴木勝; 浅井吉蔵; 山田和芳; 秋光正子; 秋光純; P; Manuel; J. M. Tranquada; G. Shirane
Oral presentation, Japanese, 日本物理学会講演概要集, 福岡
Mar. 2004

La_1-x_Pr_x_CoO_3_の電子状態
石井大基; 齋藤智彦; 岩澤英明; 山下雄司; Thant Sin Naing; 小林義彦; 浅井吉蔵
Oral presentation, Japanese, 日本物理学会講演概要集, 福岡
Mar. 2004

RENi_0.5_Mn_0.5_O_3_（RE:希土類元素）中の^55^Mn NMR
小林憲史; 浅井吉蔵; 小林義彦; 鈴木勝; 溝口森二
Oral presentation, Japanese, 日本物理学会講演概要集（日本物理学会）
Sep. 2003

La_1-x_Pr_xCoO_3_ の光電子分光
岩澤英明; 山下雄司; 齋藤智彦; タン シン ナイン; 小林義彦; 浅井吉蔵
Oral presentation, Japanese, 日本物理学会講演概要集（日本物理学会）
Sep. 2003

HoNi_2_B_2_C の超音波測定（５）
木村敏昭; 小林利章; 鈴木勝; 浅井吉蔵; 石田進; 竹屋浩幸
Oral presentation, Japanese, 日本物理学会講演概要集（日本物理学会）
Sep. 2003

LaCoO_3_ の超音波測定
Thant Sin Naing; 小林義彦; 鈴木勝; 浅井吉蔵; 近桂一郎
Oral presentation, Japanese, 日本物理学会講演概要集（日本物理学会）
Sep. 2003

HoNi_2_B_2_C における一軸圧力下磁化測定
岡本嵩; 小林義彦; 木村敏昭; 鈴木勝; 浅井吉蔵; 竹屋浩幸
Oral presentation, Japanese, 日本物理学会講演概要集（日本物理学会）
Sep. 2003

Elastic Constants of HoNi_2_B_2_C
Masaru Suzuki; Toshiaki Kimura; Miki Suetake; Youko Takahashi; Kichizo Asai; Susumu Isida; Hiroyuki Takeya
Oral presentation, English, Internal Conference on Magnetism (ICM 2003) Abstract book
Aug. 2003

Pressure-Induced Charge-Transfer Phase Transition in a Mixed-Valence Iron Complex
Yoshihiko Kobayashi; Miho Itoi; Norimichi Kojima; Kichizo Asai
Oral presentation, English, International Conference on Magnetism (ICM2003) abstract book
Aug. 2003

Magnetic and Transport Properties in RECoO_3_ Single Crystals (RE=La, Pr, Nd)
Yoshihiko Kobayashi; Teppei Nakajima; Kichizo Asai
Oral presentation, English, International Conference on Magnetism (ICM 2003) abstract book
Aug. 2003

LaCoO_3_のスピン転移
浅井吉蔵
Oral presentation, Japanese, 化合物新磁性材料専門研究会（資料 no.2） ２００２年度研究会講演概要集
Mar. 2003

LaCoO_3_のスピン転移
浅井吉蔵
Invited oral presentation, Japanese, 化合物新磁性材料専門研究会（資料 no.2） ２００２年度研究会講演概要集
Mar. 2003

リエントラント超伝導体HoNi_2_B_2_Cの超伝導特性
岡本崇; 小林義彦; 木村敏昭; 鈴木勝; 浅井吉蔵; 竹屋浩幸; 鳴海康雄; 勝又紘一
Oral presentation, Japanese, 日本物理学会講演概要集
Mar. 2003

RECoO_3_単結晶（RE=La, Pr, Nd）の磁性と熱電能
小林義彦; 中島鉄平; 浅井吉蔵
Oral presentation, Japanese, 日本物理学会講演概要集
Mar. 2003

La_1-x_Ca_x_CoO_3_の磁性と金属－絶縁体転移
牟田健二郎; 小林義彦; 浅井吉蔵
Oral presentation, Japanese, 日本物理学会講演概要集
Sep. 2002

RECo_1-x_Ni_x_O_3_単結晶(RE=Pr, Nd)の磁性と熱電能
小林義彦; 中島鉄平; 浅井吉蔵
Oral presentation, Japanese, 日本物理学会講演概要集
Sep. 2002

鉄混合原子価錯体(C_n_H_2n+1_)_4_N[Fe^II^Fe^III^(dto)_3_]の電荷移動相転移の圧力効果??
小林義彦; 糸井充穂; 小島憲道; 浅井吉蔵
Oral presentation, Japanese, 日本物理学会講演概要集
Sep. 2002

La_1-x_Sr_x_CoO_3_ (x=0, 0.1) パルス強磁場における磁化と磁歪
佐藤圭輔; 後藤恒昭; 小林義彦; 鈴木勝; 浅井吉蔵
Oral presentation, Japanese, 日本物理学会2001年秋期大会講演概要集
Sep. 2001

鉄混合原子価錯体(C_n_H_2n+1_)_4_N[Fe^II^Fe^III^(dto)_3_]の電荷移動相転移の圧力効果
小林義彦; 糸井充穂; 浅井吉蔵; 小島憲道
Oral presentation, Japanese, 日本物理学会2001年秋期大会講演概要集
Sep. 2001

La_1-x_Ca_x_CoO_3_ の磁性および電子輸送現象
牟田健二郎; 小林義彦; 浅井吉蔵
Oral presentation, Japanese, 日本物理学会2001年秋期大会講演概要集
Sep. 2001

LaCoO_3_の菱面晶から立方晶への構造相転移
小林義彦; 光永 徹; 藤縄 剛; 有井 忠; 末武美樹; 浅井吉蔵; 原田仁平
Oral presentation, Japanese, 日本物理学会第56回年次大会講演概要集
Mar. 2001

LaCoO_3_における強制磁歪の異常な振る舞い
佐藤桂輔; M.I. Bartashevich; 後藤恒昭; 小林義彦; 浅井吉蔵
Oral presentation, Japanese, 日本物理学会第56回年次大会講演概要集
Mar. 2001

FeRh系合金におけるホール効果および熱電能
小林義彦; 牟田健二郎; 浅井吉蔵
Oral presentation, Japanese, 日本物理学会第56回年次大会（中央大）講演概要集
Mar. 2001

LaCoO_3_磁化過程の温度依存性
佐藤桂輔; M.I. Bartashevich; 後藤恒昭; 小林義彦; 浅井吉蔵
Oral presentation, Japanese, 日本物理学会第55回年次大会講演概要集
Sep. 2000

FeRh系合金における電子輸送効果
小林義彦; 牟田健二郎; 浅井吉蔵
Oral presentation, Japanese, 日本物理学会2000年春の分科会講演概要集
Mar. 2000

フラーレンケージ内包^140^Ce(←^140^La)のγーγ摂動角相関測定(III)
佐藤渉; 末木啓介; 菊地耕一; 鈴木信三; 阿知波洋二; 中原弘道; 大久保嘉高; 浅井吉蔵; 安部文敏
Others, Japanese, 京都大学原子炉実験所専門研究会報告(KURRI-KR-49) 「放射線と原子核をプローブとした物性研究の新展開（I）」
Mar. 2000

秩序型ペロブスカイト構造をもつ酸化物強磁性体の原子核プローブによる研究
浅井吉蔵
Others, Japanese, 京都大学原子炉実験所専門研究会報告(KURRI-KR-49) 「放射線と原子核をプローブとした物性研究の新展開（I）」
Mar. 2000

ペロブスカイト型強磁性酸化物RENi_0.5_Mn_0.5_O_3_の^55^MnのNMR II
場色正昭; 小林義彦; 浅井吉蔵; 溝口森二
Oral presentation, Japanese, 日本物理学会1999年秋の分科会（岩手大学）講演概要集
Sep. 1999

NMR study of the spin-state-transitions in LaCoO_3_
Y. Kobayashi; N. Fujiwara; S. Murata; K. Asai; H. Yasuoka
Oral presentation, English, The 51-st. Yamada Conference on Strongly Correlated electron systems, August24-28,1999, Nagano, Japan.
Aug. 1999

LaCoO_3_のNMR（II）
小林義彦; 藤原直樹; 村田 暁; 浅井吉蔵; 安岡浩志
Oral presentation, Japanese, 日本物理学会1999年年会（広島）講演概要集
Mar. 1999

(Sr_1-x_Ca_x_)_14_Cu_24_O_41_の酸素1s吸収端近傍のX線吸収
長嶺晋路; 山田修義; 山崎 尚; 小林義彦; 浅井吉蔵; 鈴木智之; 藤原正美; 辛 埴
Oral presentation, Japanese, 日本物理学会1999年年会（広島）講演概要集
Mar. 1999

フラーレンケージ内包^140^Ce(←^140^La)のγーγ摂動角相関測定(II)
佐藤渉; 末木啓介; 菊地耕一; 鈴木信三; 阿知波洋二; 中原弘道; 大久保嘉高; 浅井吉蔵; 安部文敏
Others, Japanese, 京都大学原子炉実験所専門研究会報告(KURRI-KR-31)「放射線および原子核をプローブとした物性研究（III）」
Feb. 1999

PrBa_2_Cu_2_TaO_8_の電子伝導と電子状態
古谷和之; 山田修義; 山崎 尚; 伊理武男; 鈴木智之; 長嶺晋二; 小林義彦; 浅井吉蔵; 森下忠隆; 藤沢正美; 辛 埴
Oral presentation, Japanese, 第13回日本放射光学会年会・放射光科学合同シンポジウム講演予稿集
1999

フラーレンケージ内包^140^Ce（←^140^La）のγ-γ摂動角相関測定（II）
佐藤 渉; 末木啓介; 菊地耕一; 鈴木信三; 阿智波洋次; 中原弘道; 大久保嘉高; 浅井吉蔵; 安部文敏
Others, Japanese, 京都大学原子炉実験所専門研究会（熊取）「放射線および原子核をプローブした物性研究」専門研究会報告（III）
Dec. 1998

LaCoO_3_のNMR
小林義彦; 藤原直樹; 村田 暁; 浅井吉蔵; 安岡弘志
Oral presentation, Japanese, 日本物理学会秋の分科会（沖縄）講演概要集
Sep. 1998

PrBa_2_Cu_2.1_Ta_0.9_O_8_の電気伝導と電子状態
山田修義; 古谷和之; 山崎 尚; 伊理武男; 鈴木智之; 長嶺晋路; 小林義彦; 浅井吉蔵; 森下忠隆; 藤原正美; 辛 埴
Oral presentation, Japanese, 日本物理学会秋の分科会（沖縄）講演概要集
Sep. 1998

酸素位置選別励起によるPrBa_2_Cu_3_O_7_の酸素局所電子状態
山田修義; 鈴木智之; 山崎 尚; 小林義彦; 渡辺球一; 長嶺晋路; 浅井吉蔵; 伊理武男; 手塚泰久; 藤原正美; 辛 埴; JZ Liu; R. N. Shetton
Oral presentation, Japanese, 日本物理学会秋の分科会（沖縄）講演概要集
Sep. 1998

Elastic anomalies with the spin-state transitions in LaCoO_3_
S. Murata; S. Ishida; M. Suzuki; Y. Kobayashi; K. Asai; K. Kohn
Oral presentation, English, 9th International Conference on Phonon Scattering in Condensed Matter (Lancaster, UK) Abstracts
Jul. 1998

Li_0.995_Cd_0.005_NbO_3_中の^117^Inと^111^Cdの摂動角相関
大久保嘉高; 上原進一; 柴田誠一; 川瀬洋一; 中村仁; 岡田卓也; 安部静子; 安部文敏; 浅井吉蔵; 村上幸弘; 斎藤直
Others, Japanese, 京都大学原子炉実験所専門研究会報告(KURRI-KR-22) 「放射線および原子核をプローブとした物性研究（II）」
Feb. 1998

フラーレンケージ内包^140^Ce(←^140^La)のγーγ摂動角相関測定
佐藤渉; 末木啓介; 菊地耕一; 小林香奈子; 鈴木信三; 阿知波洋二; 中原弘道; 大久保嘉高; 安部文敏; 浅井吉蔵
Others, Japanese, 京都大学原子炉実験所専門研究会報告(KURRI-KR-22) 「放射線および原子核をプローブとした物性研究（II）」
1998

Local Structure and Valence of Impurity Ions in Oxides by TDPAC and Moessbauer Emission Spectroscopy
F. Ambe; Y. Ohkubo; S. Ambe; Y. Kobayashi; T. Okada; Y. Yanagida; J. Nakamura; K. Asai; Y. Kawase; S. Uehara
Keynote oral presentation, English, Radioanal. and Nucl. Chem., International conference
1995

Studies of ^99^Ru ions in metal oxides by means of time-differential perturbed-angular correlation and emission Mossbauer measurements
Y. Ohkubo; Y. Kobayashi; K. Asai; S. Ambe; K. Harasawa; T. Okada; S. Shibata; F. Ambe
Others, English, RIKEN Review
Jan. 1994

^99^Ru Mossbauer spectroscopy and magnetization studies of ruthenium trichlorides
Y. Kobayashi; K. Asai; F. Ambe
Others, English, RIKEN Review
Jan. 1994

TDPAC Studies of the After-effects of ^111^In→^111^Cd EC Decay in a-Fe_2_O_3_ and Other Inorganic Compounds
K. Asai; F. Ambe; S. Ambe; T. Okada; H. Sekizawa
Invited oral presentation, English, Radiochimica Acta., International conference
1988

日本物理学会

米国物理学会(The American Physical Society)