工学士, 東北大学

修士（工学）, 東北大学

博士（工学）, 東北大学

Physical reservoir

Superconductivity

Electrical properties: electronic conduction

Electric circuits

Solid-state devices

Manufacturing technology (mechanical, electrical/electronic, chemical engineering), Electronic devices and equipment

Manufacturing technology (mechanical, electrical/electronic, chemical engineering), Electric/electronic material engineering

Nanotechnology/Materials, Applied physics - general

01 Apr. 2009
電気通信大学, 教授

01 Apr. 2007 - 31 Mar. 2009
The University of Electro-Communications, Associate Professor

01 Apr. 2002 - 31 Mar. 2007
The University of Electro-Communications, Associate Professor

Oct. 1995 - Mar. 2002
Tohoku University, Research Associate

Apr. 1995 - Sep. 1995
Nagoya University, Research Fellow of JSPS

Feb. 1995 - Mar. 1995
Tohoku University, Research Fellow of JSPS

Apr. 1992 - Jan. 1995
Tohoku University, Research Fellow of JSPS (DC)

Jan. 1995
Tohoku University, Graduate School, Division of Engineering, Department of Electronic Engineering

Mar. 1990
Tohoku University, Faculty of Engineering, 電気工学科

Apr. 1983 - Mar. 1986
宮城県仙台第二高等学校, 普通科, Japan

May 2006 - Present
超伝導エレクトロニクス研究専門委員会委員, 電子情報通信学会, Society

Nov. 2023 - Oct. 2025
ニューロモルフィック回路実装に向けたハードウェアに関する調査専門委員会, 電気学会, Society

Jul. 2024 - Jun. 2025
編集委員, 電子情報通信学会『Special Section on Expanding Superconducting Digital Circuit Applications and Their Design Technology』 英文論文誌小特集編集委員会, Society

Jun. 2023 - Jun. 2024
委員長, 電子情報通信学会 エレクトロニクスソサイエティ 回路・デバイス・境界技術領域委員会, Society

Jun. 2022 - Jun. 2023
副委員長, 電子情報通信学会 エレクトロニクスソサイエティ 回路・デバイス・境界技術領域委員会, Society

03 Jun. 2021 - Jun. 2023
委員長, 電子情報通信学会 超伝導エレクトロニクス研究専門委員会, Society

Oct. 2010 - Mar. 2023
通信・情報処理分科会委員, 日本学術振興会 超伝導エレクトロニクス第146委員会, Society

Jul. 2018 - Mar. 2019
『Special Section on Superconducting Electronics for Quantum Information Technologies』英文論文誌小特集編集委員会 編集委員, 電子情報通信学会, Society

Oct. 2013 - Mar. 2017
位相エンジニアリングに基づく低温エレクトロニクス調査専門委員会委員, 電気学会, Society

May 2013 - May 2016
和文論文誌Ｃ編集委員会編集委員, 電子情報通信学会, Society

Apr. 2014 - Dec. 2014
プログラム編集委員, 応用物理学会

May 2006 - May 2012
英文論文誌Ｃ編集委員会編集委員, 電子情報通信学会, Society

May 2008 - May 2011
Electronics Express編集委員会委員, 電子情報通信学会, Society

Apr. 1998 - Oct. 2010
ディジタルデバイス応用分科会委員, 日本学術振興会 第146委員会

May 2006 - May 2008
エレクトロニクスソサイエティ技術渉外幹事, 電子情報通信学会, Society

May 2004 - May 2006
超伝導エレクトロニクス研究専門委員会幹事, 電子情報通信学会, Society

Dec. 2024
一般社団法人 電子情報通信学会
シニア会員

Mar. 2013
一般社団法人 電子情報通信学会
平成24年度エレクトロニクスソサイエティ活動功労表彰

Mar. 2009
社団法人 電子情報通信学会
平成20年度エレクトロニクスソサイエティ活動功労表彰

Mar. 2003
船井情報科学振興財団 船井情報科学奨励賞

Sep. 2002
応用物理学会論文賞 JJAP論文奨励賞

May 2001
Young Scientist Award for the Presentation of an Excellent Paper, JSAP

Mar. 1997
Young Engineer Award, IEICE

Operation of RSFQ Hardware Random Number Generator Comprising Two Josephson Oscillators
Yoshinao Mizugaki; Kenta Sato; Hiroshi Shimada
Lead, IEICE Transactions on Electronics, E108-C, 6, Jun. 2025, Peer-reviwed
Scientific journal, English

単一磁束量子パルス周波数変調型D/A変換器のGHz信号生成回路への応用
林誠也; 島田宏; 水柿義直
Last, 電子情報通信学会 和文論文誌C, J107-C, 10, 330-335, Oct. 2024, Peer-reviwed
Scientific journal, Japanese

Physical reservoir application of random network of gold nanoparticles fabricated by multi-step immersion in gold colloidal solution
Kaito Kobayashi; Hiroshi Shimada; Yoshinao MIZUGAKI
Last, Japanese Journal of Applied Physics, IOP Publishing, 63, 6, 064501-1-064501-6, 16 May 2024, Peer-reviwed, Abstract

We fabricated a random network of gold nanoparticles (RN-GNPs) over 12 NiCr/Au electrodes by using a multi-step immersion method, where a sample was immersed in a gold colloid solution three times. 
Nonlinear current-voltage characteristics due to the Coulomb blockade were observed at 77 K. 
For demonstration of physical reservoir applications, input-output characteristics of the RN-GNPs were also measured in a one-input, nine-output terminal configuration. 
Distorted output voltage waveforms were obtained for a sinusoidal voltage input of 100 Hz. 
The higher-order harmonic components were confirmed in the frequency spectra of the outputs. 
The waveform reconstruction task and short-term storage capacity estimation were performed by an echo state network model with ridge regression and linear regression, respectively.
Scientific journal, English

Superconducting D/A Converters Generating Quantum Voltage Defined by the Reference Microwave Frequency and the AC Josephson Effect
Yoshinao MIZUGAKI
Lead, TEION KOGAKU (Journal of Cryogenics and Superconductivity Society of Japan), Cryogenic Association of Japan, 59, 2, 80-87, 20 Mar. 2024, Peer-reviwed
Scientific journal, Japanese

Numerical Study on Physical Reservoir Computing with Josephson Junctions
K. Watanabe; Y. Mizugaki; S. Moriya; H. Yamamoto; T. Yamashita; S. Sato
IEEE Transactions on Applied Superconductivity, 34, 3, 1700204-1-1700204-4, Jan. 2024, Peer-reviwed
Scientific journal, English

Nonlinear Signal Conversion in Gold-Nanoparticle Random Array for Physical Reservoir Applications
Y. Mizugaki; K. Fujikura; H. Shimada
Lead, Japanese Journal of Applied Physics, 63, 1, 01SP35-1-01SP35-5, Jan. 2024, Peer-reviwed
Scientific journal, English

Evaluation of True Random Number Sequences Generated by Utilizing Timing Jitters in Superconducting Integrated Circuits
Kenta Sato; Naonori Sega; Hiroshi Shimada; Yoshinao Mizugaki
Last, Journal of Physics: Conference Series, IOP Publishing, 2545, 1, 012022-012022, 08 Aug. 2023, Peer-reviwed, Abstract

A Hardware Random Number Generator (HRNG), which generates true random number sequences, is studied. In superconducting Single Flux Quantum (SFQ) circuitry, HRNGs that utilized timing jitters in trigger signals have been demonstrated. In this paper, we propose an HRNG with two oscillators to enhance stability against variation of oscillator frequencies. We investigate the characteristics of random numbers generated with the proposed HRNG not only by numerical simulation but also by experiments using Nb test circuits. In the numerical simulation, the probability of “1” in random number sequences has a local minimum of “1” output probability at conditions where f_clk (the clock oscillator frequency) and f_gate (the gate oscillator frequency) are approximately equal (f_clk ≈ f_gate) for f_clk ≤ 60 GHz. It is also found that pass rates for the FIPS140-2 random number tests are little affected by variations of f_clk at f_gate = 69.2 GHz. The random number generation rate for f_clk = 60 GHz and f_gate = 43 GHz reaches 3.98 GHz. In experimental measurements, random numbers of 1 Mbits generated by a test circuit pass the SP800-22 random number tests at f_clk = 48.79 GHz and f_gate = 19.81 GHz.
Scientific journal, English

Random Number Generation Utilizing Timing Jitters of Single-Flux-Quantum Propagation
Y. Mizugaki; K. Sato; H. Shimada; T. Onomi
Lead, Proceedings of 2023 PhotonIcs & Electromagnetics Research Symposium (PIERS2023), 1744-1748, Aug. 2023, Peer-reviwed
International conference proceedings, English

マイクロコントローラを利用した金ナノ粒子誘電泳動の自動停止機構
浦江哲也; 島田 宏; 水柿義直
Last, 電子情報通信学会 和文論文誌C, 電子情報通信学会, J105-C, 11, 339-341, 01 Nov. 2022, Peer-reviwed
Scientific journal, Japanese

Operation of a 4-bit RSFQ digital-to-analog converter based on a binary split-confluence configuration
N. Sega; Y. Somei; H. Shimada; Y. Mizugaki
Last, Journal of Physics: Conference Series, IOP, 2323, 012033-1-012033-7, 17 Aug. 2022, Peer-reviwed
International conference proceedings, English

100 GHz operation of a 4-bit single-flux-quantum pulse-frequency modulator designed for bipolar D/A conversion
Y. Mizugaki; N. Sega; H. Shimada
Lead, IEICE Electronics Express (ELEX), IEICE, 19, 12, 20220194-1-20220194-4, 25 Jun. 2022, Peer-reviwed
Scientific journal, English

Evaluation of True Random Number Generator Utilizing Timing Jitters in RSFQ Logic Circuits
K. Sato; N. Sega; Y. Somei; H. Shimada; T. Onomi; Y. Mizugaki
Last, IEICE Transactions on Electronics, IEICE, E105-C, 6, 296-299, 01 Jun. 2022, Peer-reviwed
Scientific journal, English

Sensitive phonon detection using a single Cooper-pair transistor
J. Tanarom; T. Watanabe; Y. Mizugaki; H. Shimada
Applied Physics Express, IOP, 15, 6, 064001-1-064001-5, 17 May 2022, Peer-reviwed
Scientific journal, English

Planarized Nb 4-Layer Fabrication Process for Superconducting Integrated Circuits and Its Fabricated Device Evaluation
S. Nagasawa; M. Tanaka; N. Takeuchi; Y. Yamanashi; S. Miyajima; F. China; T. Yamane; K. Yamazaki; Y. Somei; N. Sega; Y. Mizugaki; H. Myoren; H. Terai; M. Hidaka; N. Yoshikawa; A. Fujimaki
IEICE Transactions on Electronics, IEICE, E104-C, 9, 435-445, 01 Sep. 2021, Peer-reviwed
Scientific journal, English

Enhanced Operation Frequencies of Bipolar Double-Flux-Quantum Amplifiers Fabricated Using 10-kA/cm2 Nb/AlOx/Nb Integration Process
Y. Somei; H. Shimada; Y. Mizugaki
Last, Japanese Journal of Applied Physics, Japan Society of Applied Physics, Institute of Physics, 60, 7, 073001-1-073001-7, 01 Jul. 2021, Peer-reviwed
Scientific journal, English

Scalability of supercurrent modulable with single Cooper-pair transistors connected in parallel
J. Tanarom; Y. Mizugaki; H. Shimada
Japanese Journal of Applied Physics, IOP, 60, 7, 074003-1-074003-7, 24 Jun. 2021, Peer-reviwed
Scientific journal, English

Nanoscale Tunnel Junctions and Metallic Single-Electron Transistors Via Shadow Evaporation and in-situ Atomic Layer Deposition of Tunnel Barriers
H. Shimada; T. Koike; K. Kikkawa; H. Konno; N. Ito; R. Kobayashi; Y. Mizugaki; K. Kanomata; M. Miura; F. Hirose
ACS Applied Nano Materials, 4, 2, 1401-1410, 26 Feb. 2021, Peer-reviwed
Scientific journal, English

Rapid Single-Flux-Quantum NOR Logic Gate Realized through the Use of Toggle Storage Loop
Yoshinao MIZUGAKI; Koki YAMAZAKI; Hiroshi SHIMADA
Lead, IEICE Transactions on Electronics, Institute of Electronics, Information and Communications Engineers ({IEICE}), E103-C, 10, 547-549, 01 Oct. 2020, Peer-reviwed
Scientific journal, English

Hardware Random Number Generator Using Josephson Oscillation and SFQ Logic Circuits
Takeshi Onomi; Yoshinao Mizugaki
Last, IEEE Transactions on Applied Superconductivity, Institute of Electrical and Electronics Engineers ({IEEE}), 30, 7, 1-5, Oct. 2020, Peer-reviwed
Scientific journal, English

Design and Error-Rate Evaluation of RSFQ Logic Gates Comprising a Toggle Storage Loop
K. Yamazaki; H. Shimada; Y. Mizugaki
Last, Journal of Physics: Conference Series, IOP, 1590, 012042-1-012042-7, 31 Jul. 2020, Peer-reviwed
International conference proceedings, English

Capacitance extraction method of a free-standing bilayer lipid membrane formed over an aperture in a nanofabricated silicon chip
Y. Tomioka; S. Takashima; M. Moriya; H. Shimada; F. Hirose; A. Hirano-Iwata; Y. Mizugaki
Last, Japanese Journal of Applied Physics, Japan Society of Applied Physics, 59, SI, SIIK02-1-SIIK02-5, Jun. 2020, Peer-reviwed, © 2020 The Japan Society of Applied Physics. A bilayer lipid membrane (BLM) is the main component of the cell membrane of living organisms, which can be formed artificially. Although the specific capacitance of a BLM is known to be in the range of 0.4-1.0 μF cm-2, many previous works that formed free-standing BLMs over an aperture in silicon chips reported larger values beyond this typical range, which suggests that equivalent-circuit models are not adequate. In this work, we modified the equivalent-circuit model by adding a resistance element of silicon. To evaluate the validity of the modified model, we applied the model to the results of electrochemical impedance spectroscopy for free-standing BLMs formed over an aperture in nanofabricated silicon chips. The derived specific capacitance values were 0.57 ± 0.08 μF cm-2, which settles in the typical range.
Scientific journal, English

Cooper-Pair Tunneling in Small Josephson Junction Arrays Under Radio-Frequency Irradiation
Godwill Mbiti Kanyolo; Kouichi Takeda; Yoshinao Mizugaki; Takeo Kato; Hiroshi Shimada
Journal of Low Temperature Physics, Springer Science and Business Media {LLC}, 200, 269-284, Jun. 2020, Peer-reviwed
Scientific journal, English

Dielectrophoretic Assembly of Gold Nanoparticle Arrays Evaluated in Terms of Room-Temperature Resistance
Y. Mizugaki; M. Moribayashi; T. Yagai; M. Moriya; H. Shimada; A. Hirano-Iwata; F. Hirose
Lead, IEICE Transactions on Electronics, IEICE, E103-C, 2, 62-65, 01 Feb. 2020, Peer-reviwed, Copyright © 2020 The Institute of Electronics, Information and Communication Engineers Gold nanoparticles (GNPs) are often used as island electrodes of single-electron (SE) devices. One of technical challenges in fabrication of SE devices with GNPs is the placement of GNPs in a nanogap between two lead electrodes. Utilization of dielectrophoresis (DEP) phenomena is one of possible solutions for this challenge, whereas the fabrication process with DEP includes stochastic aspects. In this brief paper, we present our experimental results on electric resistance of GNP arrays assembled by DEP. More than 300 pairs of electrodes were investigated under various DEP conditions by trial and error approach. We evaluated the relationship between the DEP conditions and the electric resistance of assembled GNP arrays, which would indicate possible DEP conditions for fabrication of SE devices.
Scientific journal, English

Design and operation of distributed double-SQUID amplifier for RSFQ circuits
Komei Higuchi; Hiroshi Shimada; Yoshinao Mizugaki
Last, Journal of Physics: Conference Series, {IOP} Publishing, 1293, 012060-012060, 15 Oct. 2019, Peer-reviwed
Scientific journal, English

1000-Fold Double-Flux-Quantum Voltage Multiplier Employing Directional Propagation of Flux Quanta Through Asymmetrically Damped Junction Branches
Yoshinao Mizugaki; Yuma Arai; Tomoki Watanabe; Hiroshi Shimada
IEEE Transactions on Applied Superconductivity, Institute of Electrical and Electronics Engineers ({IEEE}), 29, 5, 1-5, Aug. 2019, Peer-reviwed
Scientific journal, English

Enhanced voltage swing of rapid-single-flux-quantum distributed output amplifier equipped with double-stack superconducting quantum interference devices
Yoshinao Mizugaki; Komei Higuchi; Hiroshi Shimada
Lead, IEICE Electronics Express, Institute of Electronics, Information and Communications Engineers ({IEICE}), 16, 14, 20190331-20190331, 25 Jul. 2019, Peer-reviwed
Scientific journal, English

Equivalent circuit model modified for free-standing bilayer lipid membranes beyond 1 TΩ
Y. Tomioka; S. Takashima; M. Moriya; H. Shimada; F. Hirose; A. Hirano-Iwata; Y. Mizugaki
Japanese Journal of Applied Physics, Institute of Physics, GB, 58, SD, SDDK02-1-SDDK02-6, 01 Jun. 2019, Peer-reviwed, © 2019 The Japan Society of Applied Physics. A cell is the basic functional unit of living organisms. Bilayer lipid membranes (BLMs), which form cell membranes can be assembled by using artificial methods. The electrochemical characteristics of BLMs are normally investigated using electrochemical impedance spectroscopy (EIS); however, the equivalent circuit need to be modified by the experimental conditions. In this study, we formed plain BLMs to determine the underlying equivalent circuit model of free-standing BLMs, and we measured the electrical characteristics using EIS. To analyze the results of EIS, we proposed equivalent circuit models including electrical double layer (EDL) effects on both sides of a BLM. We also extracted and evaluated the electrochemical parameters; the aperture-suspended BLMs using an Si chip having tapered edge recorded TΩ-order membrane resistances, which were one order higher than those reported in most previous studies. Regarding the capacitances of EDL, we compared the extracted values and the calculated results.
Scientific journal, English

Evaluation of inter-particle distance of gold nanoparticles dispersed on silane-treated substrates to fabricate dithiol-connected arrays
T. Yagai; K. Matsumoto; M. Moriyabashi; M. Moriya; H. Shimada; A. Hirano-Iwata; F. Hirose; Y. Mizugaki
Japanese Journal of Applied Physics, Institute of Physics, GB, 58, SD, SDDF09-1-SDDF09-6, 01 Jun. 2019, Peer-reviwed, © 2019 The Japan Society of Applied Physics. Small tunnel junctions using gold nanoparticles (GNPs) as electrodes have been studied to fabricate single-electron devices. GNPs connected via dithiol molecules have been used as small tunnel junctions, and a two-stage dispersion method was used to fabricate dithiol-connected GNP arrays. In this process, the GNPs were fixed on silane-treated substrates by immersing the substrate in a colloidal gold solution. For fabricating dithiol-connected arrays, the inter-particle distance of the dispersed GNPs must be smaller than the GNP diameter. Consequently, the inter-particle distance controlled by the immersion time (T IM1) was evaluated. For T IM1 values exceeding 8 h, the inter-particle distance was less than the GNP diameter. A second dispersion of GNPs after treating samples with dithiol realized particle connections. For the GNP arrays produced with T IM1 values greater than 8 h, the I-V characteristics were measured at 77 K, and the yield of devices exhibiting nonlinear I-V curves was 23%.
Scientific journal, English

Single-electron charging effects observed in arrays of gold nanoparticles formed by dielectrophoresis between SAM-coated electrodes
M. Moribayashi; T. Yagai; M. Moriya; H. Shimada; A. Hirano-Iwata; F. Hirose; Y. Mizugaki
AIP Conference Proceedings, American Institute of Physics, 2067, 020019-1-020019-8, Jan. 2019, Peer-reviwed, © 2019 Author(s). In the fabrication of single-electron (SE) devices with gold nanoparticles (GNPs), one of the technical challenges is the arrangement of GNPs into a gap between electrodes. We employed dielectrophoresis (DEP) for the GNP arrangement because it allowed flexible fabrication conditions. When we tried to arrange GNPs into a gap between electrodes, we often had an excessive current during DEP, which resulted in poor fabrication yields. It suggested that the Joule heat generated by the excessive current could break or fused arrays of GNPs when the electrodes were bridged through the arrays. In order to solve this problem, we coated the electrode surfaces with a self-assembled monolayer (SAM) of dithiol, by which high resistance between GNPs and electrodes was realized. That is, suppression of excess currents and improvement of fabrication yield were confirmed. We also demonstrated that a sample device fabricated by using this method exhibited not only the Coulomb blockade but also the Coulomb oscillation.
International conference proceedings, English

Temporal change of AC impedance measured across a free-standing bilayer lipid membrane
S. Takashima; M. Moriya; Y. Kimura; A. Hirano-Iwata; Y. Mizugaki
AIP Conference Proceedings, American Institute of Physics, 2067, 020015-1-020015-5, Jan. 2019, Peer-reviwed
International conference proceedings, English

Numerical simulation of single-electron tunneling in random arrays of small tunnel junctions formed by percolation of conductive nanoparticles
Y. Mizugaki; H. Shimada; A. Hirano-Iwata; F. Hirose
IEICE Transactions on Electronics, IEICE, E101-C, 10, 836-839, 01 Oct. 2018, Peer-reviwed, Copyright © 2018 The Institute of Electronics, Information and Communication Engineers. We numerically simulated electrical properties, i.e., the resistance and Coulomb blockade threshold, of randomly-placed conductive nanoparticles. In simulation, tunnel junctions were assumed to be formed between neighboring particle-particle and particle-electrode connections. On a plane of triangle 100 × 100 grids, three electrodes, the drain, source, and gate, were defined. After random placements of conductive particles, the connection between the drain and source electrodes were evaluated with keeping the gate electrode disconnected. The resistance was obtained by use of a SPICE-like simulator, whereas the Coulomb blockade threshold was determined from the current-voltage characteristics simulated using a Monte-Carlo simulator. Strong linear correlation between the resistance and threshold voltage was confirmed, which agreed with results for uniform one-dimensional arrays.
Scientific journal, English

One-dimensional array of small tunnel junctions fabricated using 30-nm-diameter gold nanoparticles placed in a 140-nm-wide resist groove
Y. Mizugaki; K. Matsumoto; M. Moriya; H. Shimada; A. Hirano-Iwata; F. Hirose
Japanese Journal of Applied Physics, 57, 9, 098006-1-098006-3, 08 Aug. 2018, Peer-reviwed, © 2018 The Japan Society of Applied Physics. We present percolative arrays of gold nanoparticles (NPs) formed in a resist groove. To enhance the connection probability, the width of the resist groove (140 nm) was designed to be approximately five times larger than the diameter of gold NPs (30 nm). Two-stage deposition of gold NPs was employed to form bridge connections between the source and drain electrodes. Dithiol molecules coated on surfaces of gold NPs worked as tunnel barriers. 5 of 12 samples exhibited Coulomb blockade characteristics, in one of which the gate response was confirmed.
Scientific journal, English

A double-flux-quantum amplifier with a single flux-biasing line
Yuma Arai; Yoshiaki Urai; Tomoki Watanabe; Komei Higuchi; Hiroshi Shimada; Yoshinao Mizugaki
Journal of Physics: Conference Series, {IOP} Publishing, 1054, 012062-012062, Jul. 2018, Peer-reviwed
Scientific journal, English

Magnetoresistance in single-electron transistors comprising a superconducting island with ferromagnetic leads
Yoshinao Mizugaki; Masashi Takiguchi; Nobuyuki Tamura; Hiroshi Shimada
Journal of Physics: Conference Series, Institute of Physics Publishing, 969, 1, 012154-1-012154-6, 19 Apr. 2018, Peer-reviwed, We report electric and magnetic field responses of single-electron transistors (SETs) comprising a superconducting island with ferromagnetic (FM) leads. We fabricated two SETs, one of which had relatively high resistance and the other had relatively low resistance. The SETs had two states for the gate charge: SET-ON or SET-OFF. They also had two states for the FM lead magnetization: parallel (P) or anti-parallel (AP) configuration. Current-voltage characteristics of four SET states ("P &
SET-ON," "P &
SET-OFF," "AP &
SET-ON," and "AP &
SET-OFF") were measured at approximately 0.1 K in a compact dilution refrigerator. Magnetoresistance ratio (MRR) values were obtained for the SET-ON and SET-OFF states, respectively. The higher-resistance SET1 exhibited positive MRR values for all measured bias voltages. The MRR enhancement was confirmed for the SET-OFF state, which agreed well with the co-Tunneling model. The lower-resistance SET2, on the other hand, exhibited negative and positive MRR values for higher and lower bias voltage conditions, respectively. The bias voltage for the MRR polarity reversal was changed by the gate voltage. It was also confirmed that the co-Tunneling model was partially valid for negative MRR values.
International conference proceedings, English

Formation of an aluminum nanowire by local anodization
Fukumoto Takahiro; Masataka Moriya; Yoshinao Mizugaki; Daisuke Tadaki; Teng Ma; Ayumi Hirano-Iwata; Michio Niwano; Yasuo Kimura
JSAP Annual Meetings Extended Abstracts, The Japan Society of Applied Physics, 2017.2, 1913-1913, 25 Aug. 2017
Japanese

Fabrication of resistively-coupled single-electron device using an array of gold nanoparticles
Tran Thi Thu Huong; Kazuhiko Matsumoto; Masataka Moriya; Hiroshi Shimada; Yasuo Kimura; Ayumi Hirano-Iwata; Yoshinao Mizugaki
Applied Physics A, Springer Science and Business Media {LLC}, 123, 8, 557-1-557-7, 31 Jul. 2017, Peer-reviwed
Scientific journal, English

Thermally-fluctuated single-flux-quantum pulse intervals reflected in input-output characteristics of a double-flux-quantum amplifier
Yoshinao Mizugaki; Yoshiaki Urai; Hiroshi Shimada
Journal of Physics: Conference Series, Institute of Physics Publishing, 871, 1, 012066-1-012066-6, 26 Jul. 2017, Peer-reviwed, A double-flux-quantum amplifier (DFQA) is a voltage multiplier of quantum accuracy, which we have employed at the final stage of a single-flux-quantum (SFQ) digital-to-analog converter (DAC). We recently found that experimental input-output (IO) characteristics of DFQAs were always slightly different from numerical results assuming ideally-periodic SFQ pulse trains. That is, experimental IO characteristics obtained using an over-biasing method were gradually deteriorated near their maximum operation voltages. Numerical simulation including the over-biasing method at a finite temperature suggested that the difference was likely to be attributed to thermally-fluctuated intervals of input SFQ pulses.
International conference proceedings, English

Single-Flux-Quantum Bipolar Digital-to-Analog Converter Comprising Polarity-Switchable Double-Flux-Quantum Amplifier
Yoshinao Mizugaki; Tomoki Watanabe; Hiroshi Shimada
IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 27, 4, 1400104-1-1400104-4, Jun. 2017, Peer-reviwed, We present a single-flux-quantum (SFQ)-based digital-to-analog converter (DAC) generating bipolar output voltages, in which the key component is a polarity-switchable double-flux-quantum amplifier (PS-DFQA). The DAC comprised a dc/SFQ converter, an 8-bit variable pulse-number multiplier (PNM), and a +/- 8-fold PS-DFQA integrated on a single chip. SFQ pulse-frequency modulation was employed to realize variable output voltage amplitude, for which the multiplication factor of the variable-PNM was controlled by a commercial data generator situated at room temperature. The variable-PNM realized 8-bit resolution with a multiplication factor between 0 and 255. Bias currents fed to the +8-fold PS-DFQA were polarity switched in synchronization with the digital code for the variable-PNM. The whole circuits including I/O elements were designed using SFQ cell libraries, and fabricated using a niobium integration process. Sinusoidal bipolar voltage waveform of 0.38 mV(pp) was demonstrated using a reference signal source of 43.94 MHz.
Scientific journal, English

Gate-tuned negative differential resistance observed at room temperature in an array of gold nanoparticles
Tran Thi Thu Huong; Kazuhiko Matsumoto; Masataka Moriya; Hiroshi Shimada; Yasuo Kimura; Ayumi Hirano-Iwata; Yoshinao Mizugaki
APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING, SPRINGER, 123, 4, 268-1-268-5, Apr. 2017, Peer-reviwed, We fabricated a single-electron (SE) device using gold nanoparticles (Au NPs). Drain, source, and gate electrodes on a SiO2/Si substrate were formed using electron beam lithography (EBL) and thermal evaporation of Au. Subsequently, solutions of 3-nm-diameter and 5-nm-diameter Au NPs were dropped on the device to make current paths through Au NPs among the electrodes. Measurements of the device exhibited negative differential resistance (NDR) in the current-voltage characteristics between the drain and source electrodes at room temperature (298 K). The NDR behavior was tuned by applying a gate voltage.
Scientific journal, English

Nanostructure Fabrication through a Microwire of Local Anodization
Takahiro Fukumoto; Yasuo Kimura; Toshiro Ogino; Masataka Moriya; Yoshinao Mizugaki; Daisuke Tadaki; Ma Teng; Ayumi Hirano-Iwata; Michio Niwano
2017 IEEE INTERNATIONAL MEETING FOR FUTURE OF ELECTRON DEVICES, KANSAI (IMFEDK), IEEE, 60-61, 2017, Peer-reviwed, An aluminum microwire was locally anodized to form a nanowire with triangular cross section. Nanostructure formed through local anodization depended strongly on a cross sectional shape of a microwire before anodization. The width of the nanowire was controlled by the ratio of voltage between edges of locally anodized area to anodization current. This indicates that local anodization has the potential to fabricate of nanostructures for nanodevices.
International conference proceedings, English

Three Parallel Generation of a 4-bit M-Sequence Using Single-Flux-Quantum Digital Circuits
Yoshinao Mizugaki; Yasuaki Mutoh; Yoshiaki Urai; Kazunao Sawada; Tomoki Watanabe
IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 26, 5, 1300504-1-1300504-4, Aug. 2016, Peer-reviwed, Maximum-length sequences (M-sequences) are known as pseudo-random numbers generated with relatively simple digital circuits. In this paper, we present a single-fluxquantum digital circuit that generated three output bits of a 4-bit M-sequence in one clock operation. The circuit comprised three clocked EXCLUSIVE-OR gates, one delay flip-flop, three dc/SFQ converters (for set, reset, and low-frequency clock signals), and three SFQ/dc converters (for three parallel outputs), all of which were integrated on a superconducting Nb chip. A 10-GHz clock generator was also implemented for high-speed testing. The total number of Nb/AlOx/Nb Josephson junctions was 568. Verilog simulation demonstrated correct circuit operation with a 20-GHz clock, which corresponded to the generation rate of 60 Gb/s. The measurement was carried out in a liquid helium bath. Low-speed testing with a 1-kHz clock demonstrated periodic signals of three parallelized 4-bit M-sequence. We also confirmed that the outputs were correctly shifted when 13 clock signals of 10 GHz were fed between two 1-kHz clock signals.
Scientific journal, English

Design and Operation of a Double-Flux-Quantum Amplifier Excluding Flux Bias Lines
Yoshinao Mizugaki; Tomoki Watanabe
IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 26, 5, 1301104-1-1301104-4, Aug. 2016, Peer-reviwed, In addition to their fast switching with low power dissipation, precise voltage generation is a unique feature of single-flux-quantum (SFQ) circuits. This feature is attractive for realizing ac voltage standards consisting of SFQ-based digital-to-analog converters (DACs). Among several key components in SFQ-based DACs, a double-flux-quantum amplifier (DFQA) is a potential candidate to amplify the output voltage. In this paper, we present a redesigned DFQA without flux bias lines. We found a parameter set that provided wide bias margins and zero-flux-bias operation. Improved bias regions were numerically demonstrated, whereas a +/- 20-fold DFQA excluding flux biases was fabricated using Nb integration technology and tested in a liquid helium bath.
Scientific journal, English

Fabrication of single-electron devices using dispersed nanoparticles and fitting experimental results to values calculated based on percolation model
Masataka Moriya; Tran Thi Thu Huong; Kazuhiko Matsumoto; Hiroshi Shimada; Yasuo Kimura; Ayumi Hirano-Iwata; Yoshinao Mizugaki
APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING, SPRINGER, 122, 8, 756-1-756-7, Aug. 2016, Peer-reviwed, We calculated the connection probability, P-C, between electrodes on the basis of the triangular lattice percolation model for investigating the effect of distance variation between electrodes and the electrode width on fabricated capacitively coupled single-electron transistors. Single-electron devices were fabricated via the dispersion of gold nanoparticles (NPs). The NPs were dispersed via the repeated dropping of an NP solution onto a chip. The experimental results were fitted to the calculated values, and the fitting parameters were compared with the occupation probability, P-O, which was estimated for one drop of the NP solution. On the basis of curves of the drain current versus the drain-source voltage (I-D-V-DS) measured at 77 K, the current was suppressed at approximately 0 V.
Scientific journal, English

Sharp switching characteristics of single electron transistor with discretized charge input
Masashi Takiguchi; Hiroshi Shimada; Yoshinao Mizugaki
Applied Sciences (Switzerland), MDPI AG, 6, 8, 214-1-214-8, 29 Jul. 2016, Peer-reviwed, For the low-power consumption analog and digital circuit applications based on a single-electron transistor, enhancement of its switching performance is required. Our previous works analytically and numerically demonstrated that a discretized charge input device, which comprised a tunnel junction and two capacitors, improved the gain characteristics of single-electron devices. We report the design and fabrication of an aluminum-based single-electron transistor having the discretized charge input function. Flat-plate and interdigital geometries were employed for adjusting capacitances of grounded and the coupling capacitors. The sample exhibited clear switching on input-output characteristics at the finite temperature.
Scientific journal, English

Bloch Oscillation in a One-Dimensional Array of Small Josephson Junctions
Hiroshi Shimada; Shunsuke Katori; Srinivas Gandrothula; Tomoaki Deguchi; Yoshinao Mizugaki
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, PHYSICAL SOC JAPAN, 85, 7, 074706-1-074706-6, Jul. 2016, Peer-reviwed, A distinct Bloch nose was demonstrated in the current-voltage characteristics of a one-dimensional array of 20 small Josephson junctions. Arrays of direct-current superconducting quantum interference device (dc-SQUID) structures were used as leads to the array of junctions, and the environmental impedance was tuned with a magnetic field. The observed Bloch nose had a negative differential resistance of its magnitude of as large as 14.3 M Omega, a blockade voltage of 0.36 mV, and a decrease in voltage of 0.21 mV due to the Bloch oscillation, all of which are larger than those obtained in a single junction by more than one order. The observed Bloch oscillation was quantitatively described on the basis of the Bloch oscillation of each single junction in combination with the charge soliton model in a long array. Unexpected constant-current spikes, whose origin lay in the dc-SQUID in the leads, were also observed to be superposed on the current-voltage characteristics when the Coulomb blockade appeared.
Scientific journal, English

Experimental demonstration of single-flux-quantum sequential-access mask ROM
Yoshinao Mizugaki; Kazunao Sawada; Tomoki Watanabe; Hiroshi Shimada
IEICE ELECTRONICS EXPRESS, IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG, 13, 12, 20160342-1-20160342-6, Jun. 2016, Peer-reviwed, We present a superconducting single-flux-quantum (SFQ) mask ROM comprising 2-bit storage cells and a sequential-access driver. Four types of storage cells for 2-bit data ("00," "10," "01," "11") are adopted for reduction of the cell dimensions, whereas the sequential access is suitable for a single-chip quantum voltage waveform generator implemented with an SFQ-based digital-to-analog converter. 2-bit storage cells of 60 x 70 mu m(2) are fabricated using a niobium integration technology and tested in liquid helium. Operation of a sequential-access mask ROM with data of 8 bits x 6 words is also demonstrated.
Scientific journal, English

Superconducting bipolar digital-to-analog converter equipped with dual double-flux-quantum amplifier
Yoshinao Mizugaki; Tomoki Watanabe; Hiroshi Shimada
IEICE ELECTRONICS EXPRESS, IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG, 13, 10, 20160242-1-6, May 2016, Peer-reviwed, Precise voltage generation is a unique feature of superconducting single-flux-quantum (SFQ) circuits, and hence, several SFQ-based digital-to-analog converters (DACs) have been designed for metrological applications. In this letter, we propose a dual double-flux-quantum amplifier (dual-DFQA) that extends DAC output voltage from unipolar to bipolar. An SFQ-based DAC comprising a 4-bit variable pulse number multiplier and a +/- 20-fold dual-DFQA is fabricated using a niobium integration technology. A 1-kHz, +/- 0.29-mV sinusoidal voltage waveform is successfully synthesized.
Scientific journal, English

Improvement of Single-Electron Digital Logic Gates by Utilizing Input Discretizers
Tran Thi Thu Huong; Hiroshi Shimada; Yoshinao Mizugaki
IEICE TRANSACTIONS ON ELECTRONICS, IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG, E99C, 2, 285-292, Feb. 2016, Peer-reviwed, We numerically demonstrated the improvement of single-electron (SE) digital logic gates by utilizing SE input discretizers (IDs). The parameters of the IDs were adjusted to achieve SE tunneling at the threshold voltage designed for switching. An SE four-junction inverter (FJI) with an ID (ID-FJI) had steep switching characteristics between the high and low output voltage levels. The limiting temperature and the critical parameter margins were evaluated. An SE NAND gate with IDs also achieved abrupt switching characteristics between output logic levels.
Scientific journal, English

Change in the characteristics of an array of small Josephson junctions with an application of high frequency/microwave radiation
Kanyolo G. M.; Mizugaki Y.; Shimada H.
Meeting Abstracts of the Physical Society of Japan, The Physical Society of Japan, 71, 1064-1064, 2016,

Coulomb閉塞を示すAl/AlOx/Alの微小Josephson接合を20個直列に一次元配列した素子を作製し、高周波照射に伴うその直流特性の変化を入力パワーを変えて測定した。1 MHz〜3 GHzでは、Coulomb閉塞の電圧幅は周波数によらずに印加された交流電圧振幅に比例して減少することを見出した。この結果は、古典領域の多光子吸収過程によるCooper対電荷ソリトンの注入閾電圧の低下によるものと理解でき、高周波/マイクロ波パワー検出器としての応用可能性を示唆する。

Japanese

Tunneling transport in capacitively coupled arrays of small Josephson junctions
Matsudo K.; Nishigaki H.; Mizugaki Y.; Shimada H.
Meeting Abstracts of the Physical Society of Japan, The Physical Society of Japan, 71, 1066-1066, 2016,

微小ジョセフソン接合の1次元配列2本を静電的に結合した素子においては結合の強弱、印加磁場、バイアス電圧に応じて様々な電流誘引現象が見られる。今回、結合容量が先行研究より大きな素子を作製し、測定を行った。一方の配列を零バイアスに固定し、他方に有限バイアスを与えると、低バイアス時に顕著な逆方向の電流誘引が観測された。この逆方向の誘引電流は、弱い磁場の印加で消失した。この誘引の起源はクーパー対の励起子輸送であることが示唆される。

Japanese

Detection of emission from a superconducting single-electron transistor by an array of small Josephson junctions
Nishigaki H.; Kanyolo G. M.; Mizugaki Y.; Shimada H.
Meeting Abstracts of the Physical Society of Japan, The Physical Society of Japan, 71, 1065-1065, 2016,

微小Josephson接合の1次元配列では、マイクロ波を照射すると電流電圧特性に存在するCoulombギャップがマイクロ波電圧に比例して減少する。この特性変化に基づいて、微小Josephson接合列はマイクロ波検出器となり得る。微小Josephson接合列をオンチップの輻射強度検出器とし、輻射源として超伝導単一電子トランジスタ(SSET)を用いて、SSETの特性変化に応じた輻射検出を行った結果を報告する。

Japanese

Fabrication of high temperature capacitively-and resistively-coupled single electron transistors using gold nanoparticles
H. T. T. Tran; K. Matsumoto; M. Moriya; H. Shimada; Y. Kimura; A. Hirano-Iwata; Y. Mizugaki
2016 IEEE 16TH INTERNATIONAL CONFERENCE ON NANOTECHNOLOGY (IEEE-NANO), IEEE, 131-134, 2016, Peer-reviwed, We fabricated single electron transistors (SETs) by using gold nanoparticles as their islands. With a simple method of the fabrication, characteristics of capacitively-and resistively-coupled SETs (C-SETs and R-SETs) were achieved at 77 K and room temperature.
International conference proceedings, English

Design of single-electron hysteretic inverter
Tran T. T. Huong; Y. Mizugaki
International Symposium on Nanoscale Transport and Technology (ISNTT2015), 113, 17 Nov. 2015
International conference proceedings, English

A single-electron hysteretic inverter designed for enhancement of stochastic resonance
Tran T. T. Huong; Yoshinao Mizugaki
IEICE ELECTRONICS EXPRESS, IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG, 12, 17, 20150527-1-20150527-12, Sep. 2015, Peer-reviwed, To improve stochastic resonance in a single-electron (SE) device, we propose an SE device having hysteretic characteristics. We first demonstrate by analyzing a mathematical model that the correlation coefficient between the subthreshold input and the inverter output is improved by introducing hysteresis into an ideal inverter (NOT gate). To realize hysteresis in an SE inverter, we have designed an SE device having hysteretic characteristics (2ID-FJI) by combining two input discretizers (IDs) and an SE four-junction inverter (FJI). Evaluations of the correlation coefficients prove that the 2ID-FJI can achieve a significant improvement in stochastic resonance.
Scientific journal, English

Pulse Response of Mutually-Coupled dc-to-SFQ Converter Investigated using an On-Chip Pulse Generator
Tomoki Watanabe; Yoshiaki Urai; Hiroshi Shimada; Yoshinao Mizugaki
IEICE TRANSACTIONS ON ELECTRONICS, IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG, E98C, 3, 238-241, Mar. 2015, Peer-reviwed, A readout technique using single-flux-quantum (SFQ) circuits enables superconducting single photon detectors (SSPDs) to operate at further high-speed, where a mutually-coupled dc-to-SFQ (MC-dc/SFQ) converter is used as an interface between SSPDs and SFQ circuits. In this work, we investigated pulse response of the MC-dc/SFQ converter. We employed on-chip pulse generators to evaluate pulse response of the MC-dc/SFQ converter for various pulses. The MC-dc/SFQ converter correctly operated for the pulse current with the amplitude of 52 mu A and the width of 179 ps. In addition, we examined influence of the pulse amplitude and width to operation of the MC-dc/SFQ converter by numerical simulation. The simulation results indicated that the MC-dc/SFQ converter had wide operation margins for pulse current with amplitudes of 30-60 mu A irrespective of the pulse widths.
Scientific journal, English

21aBK-10 Observation of Bloch oscillation and current plateaus in a linear array of small Josephson junctions
Shimada H.; Katori S.; Deguchi T.; Mizugaki Y.
Meeting Abstracts of the Physical Society of Japan, The Physical Society of Japan (JPS), 70, 1269-1269, 2015
Japanese

4-bit Bipolar Triangle Voltage Waveform Generator Using Single-Flux-Quantum Circuit
Tomoki Watanabe; Yoshitaka Takahashi; Hiroshi Shimada; Masaaki Maezawa; Yoshinao Mizugaki
Proceedings of the 27th International Symposium on Superconductivity (ISS 2014), ELSEVIER SCIENCE BV, 65, 213-216, 2015, SFQ digital-to-analog converters (DACs) are one of the candidates for AC voltage standards. We have proposed SFQ-DACs based on frequency modulation (FM). Bipolar output is required for applications of AC voltage standards, while our previous SFQ-DACs generated only positive voltages. In this paper, we present our design of a 4-bit bipolar triangle voltage waveform generator comprising an SFQ-DAC. The waveform generator has two output ports. Synthesized half-period waveforms are alternately generated in one of the output ports. The bipolar output is realized by observing the differential voltage between the ports. We confirmed a 72-mu V-PP bipolar triangle voltage waveform at the frequency of 35.7 Hz. (C) 2015 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
International conference proceedings, English

Quantum Interference in DC-SQUIDs Comprising Two Sub-Micron Aluminum Josephson Junctions: Deviation from Classical Model
Koji Miura; Kento Kikuchi; Hiroshi Shimada; Yoshinao Mizugaki
Proceedings of the 27th International Symposium on Superconductivity (ISS 2014), ELSEVIER SCIENCE BV, 65, 177-180, 2015, In a small Josephson junction, the critical current is often found experimentally to be smaller than the value expected from the Ambegaokar-Baratoff theory because of the quantum phase fluctuations. We also observed in our previous study that the quantum interference in a dc-SQUID comprising sub-micron Al junctions deviated from the classical model. In this work, we have fabricated 13 devices having different values of maximal critical currents, and evaluated their quantum interference patterns. The quantum interference of 12 among 13 devices has deviated from the classical model. It is confirmed that their maximal critical currents (I-csq,I-max) are reduced from the values (I-csq0) predicted by the Ambegaokar-Baratoff theory. Besides, the quantum interference for I-csq,I-max / I-csq0 < 0.4 agrees with the modified quantum-interference model. (C) 2015 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
International conference proceedings, English

Design and operation of a 9-bit single-flux-quantum pulse-frequency modulation digital-to-analog converter
Yoshinao Mizugaki; Yoshitaka Takahashi; Hiroshi Shimada; Masaaki Maezawa
Proceedings of the 27th International Symposium on Superconductivity (ISS 2014), ELSEVIER SCIENCE BV, 65, 209-212, 2015, We designed and operated a 9-bit single-flux-quantum (SFQ) digital-to-analog converter (DAC). SFQ pulse-frequency modulation (PFM) was employed for generation of variable quantum output voltage, where a 9-bit variable pulse number multiplier and a 100-fold voltage multiplier were the key components. Test chips were fabricated using a Nb Josephson integration technology. Arbitrary voltage waveforms were synthesized with the maximum voltage of 2.54 mV. For ac voltage standard applications, relationships between the DAC resolution and the synthesized waveform frequency are discussed. (C) 2015 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
International conference proceedings, English

Design and operation of a 9-bit single-flux-quantum pulse-frequency modulation digital-to-analog converter
Yoshinao Mizugaki; Yoshitaka Takahashi; Hiroshi Shimada; Masaaki Maezawa
Proceedings of the 27th International Symposium on Superconductivity (ISS 2014), ELSEVIER SCIENCE BV, 65, 209-212, 2015, Peer-reviwed, We designed and operated a 9-bit single-flux-quantum (SFQ) digital-to-analog converter (DAC). SFQ pulse-frequency modulation (PFM) was employed for generation of variable quantum output voltage, where a 9-bit variable pulse number multiplier and a 100-fold voltage multiplier were the key components. Test chips were fabricated using a Nb Josephson integration technology. Arbitrary voltage waveforms were synthesized with the maximum voltage of 2.54 mV. For ac voltage standard applications, relationships between the DAC resolution and the synthesized waveform frequency are discussed. (C) 2015 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
International conference proceedings, English

4-bit Bipolar Triangle Voltage Waveform Generator Using Single-Flux-Quantum Circuit
Tomoki Watanabe; Yoshitaka Takahashi; Hiroshi Shimada; Masaaki Maezawa; Yoshinao Mizugaki
Proceedings of the 27th International Symposium on Superconductivity (ISS 2014), ELSEVIER SCIENCE BV, 65, 213-216, 2015, Peer-reviwed, SFQ digital-to-analog converters (DACs) are one of the candidates for AC voltage standards. We have proposed SFQ-DACs based on frequency modulation (FM). Bipolar output is required for applications of AC voltage standards, while our previous SFQ-DACs generated only positive voltages. In this paper, we present our design of a 4-bit bipolar triangle voltage waveform generator comprising an SFQ-DAC. The waveform generator has two output ports. Synthesized half-period waveforms are alternately generated in one of the output ports. The bipolar output is realized by observing the differential voltage between the ports. We confirmed a 72-mu V-PP bipolar triangle voltage waveform at the frequency of 35.7 Hz. (C) 2015 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
International conference proceedings, English

Quantum Interference in DC-SQUIDs Comprising Two Sub-Micron Aluminum Josephson Junctions: Deviation from Classical Model
Koji Miura; Kento Kikuchi; Hiroshi Shimada; Yoshinao Mizugaki
Proceedings of the 27th International Symposium on Superconductivity (ISS 2014), ELSEVIER SCIENCE BV, 65, 177-180, 2015, Peer-reviwed, In a small Josephson junction, the critical current is often found experimentally to be smaller than the value expected from the Ambegaokar-Baratoff theory because of the quantum phase fluctuations. We also observed in our previous study that the quantum interference in a dc-SQUID comprising sub-micron Al junctions deviated from the classical model. In this work, we have fabricated 13 devices having different values of maximal critical currents, and evaluated their quantum interference patterns. The quantum interference of 12 among 13 devices has deviated from the classical model. It is confirmed that their maximal critical currents (I-csq,I-max) are reduced from the values (I-csq0) predicted by the Ambegaokar-Baratoff theory. Besides, the quantum interference for I-csq,I-max / I-csq0 < 0.4 agrees with the modified quantum-interference model. (C) 2015 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
International conference proceedings, English

Three Parallel Generation of a 4-bit M-Sequence Using Single-Flux-Quantum Digital Circuits
Yoshinao Mizugaki; Yasuaki Mutoh; Yoshiaki Urai; Kazunao Sawada; Tomoki Watanabe
2015 15TH INTERNATIONAL SUPERCONDUCTIVE ELECTRONICS CONFERENCE (ISEC), IEEE, -DS-P07, 2015, Peer-reviwed, Maximum-length sequences (M-sequences) are known as pseudo random numbers generated with relatively simple digital circuits. In this paper, we present a 4-bit M-sequence generator designed and fabricated using a single-flux-quantum (SFQ) logic library and a niobium integration technology. To enhance its generation rate, we have introduced a parallelization scheme where three bits are simultaneously generated in one clock operation. The circuit comprises three exclusive ORs, one delay flip-flop, two dc/SFQ converters (for SET and CLOCK signals), and three SFQ/dc converters (for three parallel outputs). A 10-GHz clock generator of 13 bits is also implemented for high speed testing. The total number of Nb/AlOx/Nb Josephson junctions is 568. Verilog simulation has demonstrated correct circuit operation at 20-GHz clock, which corresponds to the generation rate of 60 Gb/s. The measurement was carried out in a liquid helium bath with double mu-metal cans. Low speed testing with a 1-kHz clock demonstrated periodic signals of three parallelized 4-bit M-sequence; (0, 1, 0), (1, 1, 1), (1, 0, 0), (0, 1, 0), and (0, 1, 1), where (out1, out2, out3) represents the signals from the output ports. We also confirmed that the output signals were correctly shifted when 10-GHz clocks of 13 bits were fed between two 1-kHz clock signals.
International conference proceedings, English

Design and Operation of ROM-Dedicated Single-Flux-Quantum Cell Comprising Splitters and Confluence Buffers
Kazunao Sawada; Tomoki Watanabe; Hiroshi Shimada; Yoshinao Mizugaki
2015 15TH INTERNATIONAL SUPERCONDUCTIVE ELECTRONICS CONFERENCE (ISEC), IEEE, -DS-P12, 2015, Peer-reviwed, We have developed a single-flux-quantum (SFQ) read only memory (ROM) cell. The developed SFQ ROM cell has compatibility with an existing cell library. It comprises splitters and confluence buffers. For large integration, we have merged two 1-bit cells into one cell with peripheral elements, and we have optimized circuit parameters with an automatic optimization tool. The cell area is approximately 50% of our preliminary SFQ sequential ROM cell using the CONNECT cell library. A test circuit was fabricated using a 25 mu A/mu m(2) Nb integration process. We have confirmed correct operation for all six I/O ports. The measured bias margins were almost the same magnitude as the simulation result.
International conference proceedings, English

Modified Double-Flux-Quantum Amplifier for Bipolar Voltage Multiplication
Tomoki Watanabe; Hiroshi Shimada; Yoshinao Mizugaki
2015 15TH INTERNATIONAL SUPERCONDUCTIVE ELECTRONICS CONFERENCE (ISEC), IEEE, -DS-P13, 2015, Peer-reviwed, Single-flux-quantum (SFQ) circuits can generate highly accurate average voltage. We have developed SFQ digitalto- analog converters (DACs) for application of new ac voltage standards. In this paper, we present a bipolar voltage amplifier (BVA) based on a double flux quantum amplifier (DFQA) for generation of intrinsic bipolar voltage in an SFQ-DAC. The BVA realizes the identical multiplication factors for the positive and negative output, whereas the conventional DFQA has different multiplication factors in the bipolar output. The BVA can be used for the output stage of the SFQ-DAC. We have designed a 19-fold BVA and confirmed that the 19-fold BVA operated for input frequency of up to 31.2 GHz in positive voltage output and 33.6 GHz in negative voltage output.
International conference proceedings, English

Electric Field Effect Observed on Current-Voltage Curve of YBa2Cu3O7-delta Nano-Channel with Laterally Placed Gate Electrode
Masataka Moriya; Yoshinao Mizugaki; Tomohiro Nitta; Shinji Kawaragi
2015 15TH INTERNATIONAL SUPERCONDUCTIVE ELECTRONICS CONFERENCE (ISEC), IEEE, -MF-P05, 2015, Peer-reviwed, A nano-channel with a laterally placed gate electrode was fabricated using a YBa2Cu3O7-delta film on a SrTiO3 substrate. Current-voltage curves were measured at various applied gate voltages at 4.2 K. The current increased with decreasing the gate voltage. The carrier concentration was modified by the applied gate voltage. At the small source-drain voltage, the physical factor derived from superconductivity also has an influence.
International conference proceedings, English

Observation of Zero Crossing Shapiro Step on Current-Voltage Curve of Long YBa2Cu3O7-delta Bicrystal Josephson Junction Having Tilted Field Dependence
Masataka Moriya; Takato Tokuyama; Yoshinao Mizugaki; Haruna Takahashi
2015 15TH INTERNATIONAL SUPERCONDUCTIVE ELECTRONICS CONFERENCE (ISEC), IEEE, -HF-P11, 2015, Peer-reviwed, A YBa2Cu3O7-delta bicrystal Josephson junction was fabricated by electron beam lithography and Ar ion beam etching. The width of the junction (W) was 12 mu m and the Josephson penetration length (lambda(J)) was calculated to be 2.36 mu m. As W/lambda(J) is 5.1, this bicrystal junction is a long Josephson junction. In critical current - magnetic field characteristics, periodicity is not observed, but the maximum value and the minimum value of the critical current are different at a finite magnetic field. In the I-V curve with irradiating the rf signal, the rounded Shapiro step was observed. By applying the magnetic field, the rounded 1st Shapiro step across the zero current axis was observed.
International conference proceedings, English

Magnetization switching assisted by bias voltage in a single electron transistor comprising an aluminum island and cobalt leads
A. Elarabi; M. Moriya; H. Shimada; Y. Mizugaki
The 9th International Symposium on Intrinsic Josephson Effects and THz Plasma Oscillations in High-Tc Superconductors (THz-PLASMA 2014), Nano-6, 02 Dec. 2014
International conference proceedings, English

Splitter-Based SFQ Sequential Read Only Memory
K. Sawada; T. Watanabe; Y. Urai; Y. Mutoh; Y. Mizugaki
Proceedings of Superconducting SFQ VLSI Workshop (SSV 2014), 45-48, 01 Dec. 2014
International conference proceedings, English

7-bit Single-Flux-Quantum Maximum-Length-Sequence Generator Implemented with 32-Fold Pulse Number Multiplier
Y. Mutoh; K. Sawada; T. Watanabe; Y. Urai; Y. Mizugaki
Proceedings of Superconducting SFQ VLSI Workshop (SSV 2014), 63-66, 01 Dec. 2014
International conference proceedings, English

Characterization of superconducting single-electron transistors with small Al/AlOx/V Josephson junctions
Hiroshi Shimada; Kenji Miyawaki; Ayano Hagiwara; Kouichi Takeda; Yoshinao Mizugaki
SUPERCONDUCTOR SCIENCE & TECHNOLOGY, IOP PUBLISHING LTD, 27, 11, 115015-1-115015-8, Nov. 2014, Peer-reviwed, Superconducting single-electron transistors (SSETs) composed of small Al/AlOx/V junctions were fabricated, and their transport properties were investigated. The device with an Al island exhibited a supercurrent that was 2e-periodic in the gate charge while that with a V island showed a periodicity of e, where e is an elementary charge. The Josephson-quasiparticle (JQP)cycle current appeared at the bias voltage V in the range. Delta(Al) + Ec < e vertical bar V vertical bar < Delta(Al) + 3E(c), where. Delta(Al) is the superconducting gap of Al and Ec is the charging energy of an elementary charge. This is different from the commonly accepted range for the JQP current such as that in the case of an all Al SSET. There also appeared a large leakage current at 2 Delta(Al) <= e vertical bar V vertical bar < 2(Delta(V) + Delta(Al)+ E-c), where Delta V is the superconducting gap of V. All these properties are accounted for by considering the finite subgap quasiparticle density of states in the V electrode.
Scientific journal, English

9 bit superconductive single-flux-quantum digital-to-analogue converter
Y. Mizugaki; Y. Takahashi; H. Shimada; M. Maezawa
ELECTRONICS LETTERS, INST ENGINEERING TECHNOLOGY-IET, 50, 22, 1637-1638, Oct. 2014, Peer-reviwed, The design and operation of a 9 bit superconductive single-flux-quantum (SFQ) digital-to-analogue converter (DAC) are presented. The DAC comprises a 9 bit variable SFQ pulse number multiplier and a 100-fold voltage multiplier. An SFQ pulse-frequency modulation technique is employed for coding the analogue output voltage. The DAC is fabricated using an Nb Josephson integration technology. Its output voltage waveform, the amplitude of which is up to 2.54 mV(pp), is controlled by digital input signals from a room-temperature data generator.
Scientific journal, English

Input-output characteristics of a 999-stage double-flux-quantum amplifier designed for 1000-fold voltage multiplication
Yoshinao Mizugaki; Yusuke Sato; Hiroshi Shimada; Masaaki Maezawa
JAPANESE JOURNAL OF APPLIED PHYSICS, IOP PUBLISHING LTD, 53, 5, 053101-1-053101-4, May 2014, Peer-reviwed, We evaluate the input output characteristics of a 1000-fold voltage multiplier designed for single-flux-quantum (SFQ) digital-to-analog converters. The voltage multiplication is based on the double-flux-quantum amplifier (DFQA) that was originally proposed by Herr in 2005. We have designed and fabricated a 999-stage DFQA using a Nb/AlOx/Nb integration technology. In experiments, we have used two methods of feeding the input SFQ pulse train. The one is an overbiasing method, i.e., the input SFQ pulse train is generated at an overbiased input junction. A 1000-fold voltage multiplication with errors less than +/- 1% has been confirmed for input voltages of up to 27 mu V, of which the corresponding Josephson frequency is 13 GHz. In the other method, a dc/SFQ converter is used for feeding the input SFQ pulse train. A 1000-fold voltage multiplication with an error of -0.03% has been obtained for an input frequency of 600 MHz, of which the corresponding Josephson voltage is 1.2 mu V. In experiments, errors in measured voltages are likely to limit the accuracy in evaluation of the multiplication factor. (C) 2014 The Japan Society of Applied Physics
Scientific journal, English

Polarity Reversal of Tunnel Magnetoresistance Observed in Lateral Co-Al-Co Single-Electron Transistor
M. Takiguchi; T. Sato; H. Shimada; Y. Mizugaki
JPS Conference Proceedings, 1, 012004-1-012004-5, 24 Mar. 2014, Peer-reviwed
International conference proceedings, English

微小トンネル接合列の離散的な電荷特性を利用した単一電子シュミットトリガの設計
滝口将志; 水柿義直
電子情報通信学会和文論文誌C, The Institute of Electronics, Information and Communication Engineers, J97-C, 3, 112-117, 01 Mar. 2014, Peer-reviwed, 我々は微小トンネル接合列の離散的な電荷特性を利用し,シュミットトリガ動作する単一電子デバイスを提案する.このデバイスは,単一電子トラップと単一電子トランジスタから構成される.入力は単一電子トラップヘの入力電圧,出力は単一電子トランジスタを流れるトンネル電流とし,ヒステリシスを伴う単一電子トラップの電荷特性を利用してシュミットトリガ動作を実現する.本研究では,デバイス内の静電容量の設計に関して二つの工夫を施す.第一に単一電子トラップと単一電子トランジスタの結合部にキャパシタを追加させることで,単一電子トランジスタの出力電流が入力信号に対して急しゅんな応答となり,かつヒステリシスがバイアス電圧の影響を受けないようにした.第二に単一電子シュミットトリガのヒステリシス幅を単一電子トラップのみで設計可能とするモデルを考案した.設計した静電容量パラメータにて数値計算を行い,入出力特性が急しゅんな応答となり,かつ設計したしきい値電圧でシュミットトリガとして動作することを確認した.
Scientific journal, Japanese

Demonstration of 6-bit, 0.20-mV(pp) Quasi-Triangle Voltage Waveform Generator Based on Pulse-Frequency Modulation
Yoshitaka Takahashi; Hiroshi Shimada; Masaaki Maezawa; Yoshinao Mizugaki
IEICE TRANSACTIONS ON ELECTRONICS, IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG, E97C, 3, 194-197, Mar. 2014, Peer-reviwed, We present our design and operation of a 6-bit quasi-triangle voltage waveform generator comprising three circuit blocks; an improved variable Pulse Number Multiplier (variable-PNM), a Code Generator (CG), and-a Double-Flux-Quantum Amplifier (DFQA). They are integrated into a single chip using a niobium Josephson junction technology. While the multiplication factor of our previous m-bit variable-PNM was limited between 2(m-1) and 2(m), that of the improved one is extended between 1 and 2(m). Correct operations of the 6-bit variable-PNM are confirmed in low-speed testing with respect to the codes from the CG, whereas generation of a 6-bit, 0.20 mV(pp) quasi-triangle voltage waveform is demonstrated with the 10-fold DFQA in high-speed testing.
Scientific journal, English

Design and operation of 6-bit, 0.25-mV(pp) quasi-sine voltage waveform generator based on SFQ pulse-frequency modulation
Yoshitaka Takahashi; Hiroshi Shimada; Masaaki Maezawa; Yoshinao Mizugaki
PROCEEDINGS OF THE 26TH INTERNATIONAL SYMPOSIUM ON SUPERCONDUCTIVITY (ISS 2013), ELSEVIER SCIENCE BV, 58, 220-223, 2014, A digital-to-analogue converter (DAC) consisting of single-flux-quantum (SFQ) circuitry is known to generate accurate analogue voltages defined by the Josephson relationship. We have been developing SFQ-DACs of the pulse-frequency modulation (PFM) type. Toward voltage standard applications of SFQ-DACs, we have set the target values for the voltage amplitude and resolution at 20 mV(pp) and 10 bits, respectively. So far, we have reported a 5-bit, 10-mu V-pp quasi-sine voltage waveform generator comprising a PFM-type SFQ-DAC integrated with an on-chip digital code generator. Its small peak-to-peak voltage amplitude was due to the lack of an on-chip voltage multiplier (VM). In this paper, we present a 6-bit, 0.25-mV(pp) quasisine voltage waveform generator integrated with a 10-fold VM. The resolution is improved by introducing efficient logic sequences into the SFQ-DAC. (C) 2014 The Authors. Published by Elsevier B.V.
International conference proceedings, English

Precision improvement of the current multiplier based on the quantum current-mirror effect
Kouichi Takeda; Chihiro Ishida; Srinivas Gandrothula; Yoshinao Mizugaki; Hiroshi Shimada
Japanese Journal of Applied Physics, 53, 2, 023101, 2014, Peer-reviwed, The relationship between the coupling strength and the uncertainty in current duplication was investigated for the quantum current-mirror effect in capacitively coupled arrays of small Josephson junctions. With the increase in the coupling factor ?, defined as Cc=C, with Cc being the coupling capacitance and C the capacitance of the junction, the uncertainty decreased rapidly, especially at 1, and the standard deviation of the error reached as low as the order of 10 fA at 2:4. On this basis, we fabricated a 10-fold current multiplier composed of 11 simple arrays of junctions coupled more strongly (0:5), using a plate-capacitor structure, than a previously studied multiplier (0:01). It demonstrated more precise current-multiplication behavior than the previous multiplier with no intentional coupling structure, and the standard deviation of the error in current multiplication was decreased to less than 1/10 of the previous result. © 2014 The Japan Society of Applied Physics.
Scientific journal, English

Correlation between polarity of magnetoresistance ratio and tunnel resistance in ferromagnetic single-electron transistor with superconductive island
Masashi Takiguchi; Hiroshi Shimada; Yoshinao Mizugaki
Japanese Journal of Applied Physics, Japan Society of Applied Physics, 53, 4, 043101-1-043101-4, 2014, Peer-reviwed, We report on the correlation between the polarity of magnetoresitance ratios and the tunnel resistance observed in ferromagnetic single-electron transistors with a superconductive island (FM-SC-FM SETs). Negative magnetoresistance ratios are observed at approximately the superconductive gap voltages, which indicates that an excessive number of spin-polarized quasiparticles accumulated in a superconductive island suppress the superconductive gaps. Since the spin polarization in a superconductor decays with time, the spin injection rate should be high enough to observe the suppression of superconductive gaps. The spin injection rate at a certain bias voltage is inversely proportional to the tunnel resistance
hence, the polarity of magnetoresistance ratio should correlate with the tunnel resistance. We fabricated 26 FM-SC-FM SETs. Samples having tunnel resistances lower than 100 kΩ exhibited negative magnetoresistance ratios, while samples having tunnel resistances higher than 600 kΩ exhibited positive magnetoresistance ratios. © 2014 The Japan Society of Applied Physics.
Scientific journal, English

Zero-crossing Shapiro step generated in a niobium in-line Josephson gate
Yoshinao Mizugaki; Haruna Takahashi; Hiroshi Shimada
IEICE ELECTRONICS EXPRESS, IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG, 11, 6, 20140054-1-20140054-5, 2014, Peer-reviwed, We demonstrate a zero-crossing Shapiro step generated in a magnetically-coupled Josephson gate, where a long Josephson junction and a control line are placed in-line. The operation is based on the imbalanced evolution of the junction phases owing to the different amplitudes of the positive and negative critical current. A test circuit was fabricated using a Nb/AlOx/Nb junction technology. When we applied a rf signal of 15.2 GHz, we observed a Shapiro step that crossed the zero-current axis at the voltage position of the 1st order. The experimental results were quantitatively reproduced by simulation.
Scientific journal, English

Design and operation of 6-bit, 0.25-mV(pp) quasi-sine voltage waveform generator based on SFQ pulse-frequency modulation
Yoshitaka Takahashi; Hiroshi Shimada; Masaaki Maezawa; Yoshinao Mizugaki
PROCEEDINGS OF THE 26TH INTERNATIONAL SYMPOSIUM ON SUPERCONDUCTIVITY (ISS 2013), ELSEVIER SCIENCE BV, 58, 220-223, 2014, Peer-reviwed, A digital-to-analogue converter (DAC) consisting of single-flux-quantum (SFQ) circuitry is known to generate accurate analogue voltages defined by the Josephson relationship. We have been developing SFQ-DACs of the pulse-frequency modulation (PFM) type. Toward voltage standard applications of SFQ-DACs, we have set the target values for the voltage amplitude and resolution at 20 mV(pp) and 10 bits, respectively. So far, we have reported a 5-bit, 10-mu V-pp quasi-sine voltage waveform generator comprising a PFM-type SFQ-DAC integrated with an on-chip digital code generator. Its small peak-to-peak voltage amplitude was due to the lack of an on-chip voltage multiplier (VM). In this paper, we present a 6-bit, 0.25-mV(pp) quasisine voltage waveform generator integrated with a 10-fold VM. The resolution is improved by introducing efficient logic sequences into the SFQ-DAC. (C) 2014 The Authors. Published by Elsevier B.V.
International conference proceedings, English

Mutually-coupled dc/SFQ converter tested using an on-chip pulse generator
Y. Urai; T. Watanabe; Y. Takahashi; Y. Mizugaki
Proceedings of Superconducting SFQ VLSI Workshop (SSV 2013), 54-59, Nov. 2013
International conference proceedings, English

Development of Single-Chip Voltage Waveform Generators Based on SFQ Pulse-Frequency Modulation
Y. Mizugaki; K. Kuroiwa; Y. Sato; Y. Takahashi; Y. Urai; H. Shimada; M. Maezawa
Proceedings of Superconducting SFQ VLSI Workshop (SSV 2013), 48-53, Nov. 2013
International conference proceedings, English

Polarity reversal of tunnel magnetoresistance observed in lateral Co-Al-Co single-electron transistor
M. Takiguchi; T. Sato; H. Shimada; Y. Mizugaki
Abstracts of the 12th Asia Pacific Physics Conference, 9, Jul. 2013, Peer-reviwed
International conference proceedings, English

5-Bit Quasi-Sinusoidal Voltage Waveform Synthesized Using Single-Flux-Quantum Pulse-Frequency Modulation
Yoshinao Mizugaki; Keisuke Kuroiwa; Masataka Moriya; Hiroshi Shimada; Masaaki Maezawa
IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 23, 3, 834, Jun. 2013, Peer-reviwed, Synthesis of sinusoidal voltage waveform is a unique application in single-flux-quantum (SFQ) digital electronics. In this paper, the authors present a waveform synthesizer based on SFQ pulse-frequency modulation. It comprises a variable SFQ pulse-number-multiplier (PNM) and a code generator (CG) integrated on the same chip. The output voltage is determined by the multiplication factor in the variable-PNM, which is controlled by the code from the CG instead of room-temperature electronics. The variable-PNM realizes 5-bit resolution with the multiplication factors between 33 and 64. The CG generates the 5-bit codes for 16-step quasi-sinusoidal waveform. The whole circuits including I/O elements are designed using an SFQ digital cell library, and fabricated using a niobium integration process. The modulation of the multiplication factor for the 16-step quasi-sinusoidal waveform is confirmed by counting SFQ pulses in the low-speed testing, whereas the voltage waveform of 11 mu V peak-to-valley is demonstrated using a high-speed SFQ input of 156.25 MHz.
Scientific journal, English

5-Bit Quasi-Sinusoidal Voltage Waveform Synthesized Using Single-Flux-Quantum Pulse-Frequency Modulation
Yoshinao Mizugaki; Keisuke Kuroiwa; Masataka Moriya; Hiroshi Shimada; Masaaki Maezawa
IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 23, 3, 1300804 (4 pages), Jun. 2013, Peer-reviwed, Synthesis of sinusoidal voltage waveform is a unique application in single-flux-quantum (SFQ) digital electronics. In this paper, the authors present a waveform synthesizer based on SFQ pulse-frequency modulation. It comprises a variable SFQ pulse-number-multiplier (PNM) and a code generator (CG) integrated on the same chip. The output voltage is determined by the multiplication factor in the variable-PNM, which is controlled by the code from the CG instead of room-temperature electronics. The variable-PNM realizes 5-bit resolution with the multiplication factors between 33 and 64. The CG generates the 5-bit codes for 16-step quasi-sinusoidal waveform. The whole circuits including I/O elements are designed using an SFQ digital cell library, and fabricated using a niobium integration process. The modulation of the multiplication factor for the 16-step quasi-sinusoidal waveform is confirmed by counting SFQ pulses in the low-speed testing, whereas the voltage waveform of 11 mu V peak-to-valley is demonstrated using a high-speed SFQ input of 156.25 MHz.
Scientific journal, English

Bias-voltage dependence of magnetoresistance enhancement in a single-electron transistor comprising two cobalt leads and an aluminum island
Yoshinao Mizugaki; Nobuyuki Tamura; Hiroshi Shimada
JOURNAL OF APPLIED PHYSICS, AMER INST PHYSICS, 113, 15, 156101-1-3, Apr. 2013, Peer-reviwed, We present the magnetoresistance enhancement observed in a Co-Al-Co single-electron transistor (SET). The parallel and anti-parallel alignments of the magnetic domains in the Co leads are realized at the external field of 1.9 kOe by using magnetic hysteresis. The magnetoresistance ratio (MRR) is obtained as functions of the bias voltages for the on- and off-state SET, respectively. The results demonstrate that the MRR is enhanced in the off- state SET under the low biasing conditions. The theory including cotunneling processes is likely to explain the enhancement quantitatively. (C) 2013 AIP Publishing LLC.
Scientific journal, English

Design of area-reduced double-flux-quantum amplifier
Y. Urai; Y. Mizugaki
Proceedings of Superconducting SFQ VLSI Workshop for Young Scientists (SSV 2014-YS), 125-128, 05 Mar. 2013
International conference proceedings, English

Balanced Ternary Quantum Voltage Generator Based on Zero Crossing Shapiro Steps in Asymmetric Two-Junction SQUIDs
Masataka Moriya; Hiroyuki Takizawa; Yoshinao Mizugaki
IEICE TRANSACTIONS ON ELECTRONICS, IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG, E96C, 3, 334-337, Mar. 2013, Peer-reviwed, The three-bit balanced ternary quantum voltage generator was designed and tested. This voltage generator is based on zero-crossing Shapiro steps (ZCSSs) in asymmetric two-junction SQUID. ZCSSs were observed on the current-voltage curves, and maximum and minimum current of ZCSSs were almost same, respectively for the three bits. 27-step quantum voltages from -13 Phi(0)f to +13 Phi(0)f were observed by combinations of inputs of bit1, bit2 and bit3.
Scientific journal, English

Effect of charging energy on critical current of dc-SQUID comprising two sub-micron aluminum Josephson junctions
Y. Mizugaki; K. Kikuchi; M. Moriya; H. Shimada
Physica C: Superconductivity, Elsevier {BV}, 484, 206-208, Jan. 2013
Scientific journal, English

Design and operation of 1000-fold voltage multiplier based on double-flux-quantum amplifier
Y. Sato; M. Moriya; H. Shimada; Y. Mizugaki; M. Maezawa
PROCEEDINGS OF THE 25TH INTERNATIONAL SYMPOSIUM ON SUPERCONDUCTIVITY (ISS2012), ELSEVIER SCIENCE BV, 45, 221-224, 2013, Rapid-single-flux-quantum digital-to-analogue converters (RSFQ-DACs) are now under development for ac voltage standard applications. The voltage multiplier (VM), which precisely amplifies the input voltage, is a key component for RSFQ-DACs. Because the amount of bias current for a conventional VM increases in proportion to its multiplication factor, we have been looking for a VM device which is operated on a different principle. In this paper, we report our design of a 1000-fold VM comprising double flux quantum amplifiers (DFQAs) of which the amount of bias current is independent of its multiplication factor. Test circuits were fabricated using a 2.5 kA/cm(2) Nb process. We confirm that the experimental results demonstrate the 1000-fold operation up to 13.2 GHz input SFQ pulse repetition frequency. (C) 2013 The Authors. Published by Elsevier B.V.
International conference proceedings, English

Numerical demonstration of blocking oscillation in resistive superconducting quantum interference devices
Y. Mizugaki
PROCEEDINGS OF THE 25TH INTERNATIONAL SYMPOSIUM ON SUPERCONDUCTIVITY (ISS2012), ELSEVIER SCIENCE BV, 45, 205-208, 2013, Peer-reviwed, The author numerically demonstrates several features of blocking oscillation in resistive superconducting quantum interference devices (RSQUIDs) including two Josephson junctions. The key for the blocking oscillation is a combination of discrete and continuous flux transfer into/from the RSQUID loop. The discrete flux transfer takes place through the Josephson junctions, while the dissipative element (resistor) in the loop allows the continuous flux transfer. Three features of the blocking oscillation are presented by numerical simulation. Firstly, switching events alternately occur in the two junctions. Next, a finite average voltage is induced in the RSQUID, when the blocking oscillation is synchronized with an external rf signal. Finally, blocking oscillation modes including several intermittent periods are generated in coupled-RSQUIDs. (C) 2013 The Authors. Published by Elsevier B.V.
International conference proceedings, English

Design and operation of 1000-fold voltage multiplier based on double-flux-quantum amplifier
Y. Sato; M. Moriya; H. Shimada; Y. Mizugaki; M. Maezawa
PROCEEDINGS OF THE 25TH INTERNATIONAL SYMPOSIUM ON SUPERCONDUCTIVITY (ISS2012), ELSEVIER SCIENCE BV, 45, 221-224, 2013, Peer-reviwed, Rapid-single-flux-quantum digital-to-analogue converters (RSFQ-DACs) are now under development for ac voltage standard applications. The voltage multiplier (VM), which precisely amplifies the input voltage, is a key component for RSFQ-DACs. Because the amount of bias current for a conventional VM increases in proportion to its multiplication factor, we have been looking for a VM device which is operated on a different principle. In this paper, we report our design of a 1000-fold VM comprising double flux quantum amplifiers (DFQAs) of which the amount of bias current is independent of its multiplication factor. Test circuits were fabricated using a 2.5 kA/cm(2) Nb process. We confirm that the experimental results demonstrate the 1000-fold operation up to 13.2 GHz input SFQ pulse repetition frequency. (C) 2013 The Authors. Published by Elsevier B.V.
International conference proceedings, English

Current Multiplication Using Arrays of Small Josephson Junctions
Srinivas Gandrothula; Kenta Nakamura; Masashi Takiguchi; Yoshinao Mizugaki; Hiroshi Shimada
JAPANESE JOURNAL OF APPLIED PHYSICS, JAPAN SOC APPLIED PHYSICS, 51, 12, 123101-1-5, Dec. 2012, Peer-reviwed, We report our observation of a current-multiplication trend in a new class of current-multiplier designs based on the quantum current-mirror effect in coupled arrays of small Josephson junctions. We demonstrate an extension of the current doubler device to 8- and 10-fold current multipliers by including additional Josephson junction arrays with simplified device geometry. The devices showed the expected current-multiplication trend at low temperatures where the charging effect was dominant. The magnitude of the current that exhibited such a multiplication trend was as large as 0.8 nA. (C) 2012 The Japan Society of Applied Physics
Scientific journal, English

Numerical Demonstration of Blocking Oscillation in Resistive Superconducting Quantum Interference Devices
Y. Mizugaki
Program & Abstracts of 25th International Symposium on Superconductivity (ISS 2012), 247, Dec. 2012
International conference proceedings, English

Prototypes of Voltage Waveform Synthesizer Based on Single-Flux-Quantum Pulse-Frequency Modulation
Y. Mizugaki; K. Kuroiwa; Y. Sato; Y. Takahashi; H. Shimada; M. Maezawa
Proceedings of Superconducting SFQ VLSI Workshop (SSV 2012), 71-76, Dec. 2012
International conference proceedings, English

Drag Current Reversal in Capacitively Coupled Arrays of Small Josephson Junctions
Hiroshi Shimada; Chihiro Ishida; Yoshinao Mizugaki
PHYSICAL REVIEW LETTERS, AMER PHYSICAL SOC, 109, 19, 196801-1-5, Nov. 2012, Peer-reviwed, The current-voltage characteristics of two long capacitively coupled one-dimensional arrays of small Josephson junctions were measured, where the coupling capacitance was comparable with the capacitance of the junction. The current in both arrays was simultaneously measured at various applied magnetic fields with the voltage applied to only one of the arrays. The current was induced in the unbiased array beyond the threshold voltage for the Coulomb blockade of the biased array. The direction of the induced current is the same as that of the current in the other array when the applied magnetic field is small and Cooper-pair tunneling is dominant, while it changes to the opposite direction when the applied magnetic field is large and single-electron tunneling is dominant. This suggests that the current induction mechanism between arrays of small Josephson junctions is substantially different from that in arrays of small normal tunnel junctions.
Scientific journal, English

Positive and Negative Magneto Resistance Ratio in Ferromagnetic-Superconductor-Ferromagnetic Single-Electron Transistor
M. Takiguchi; M. Moriya; H. Shimada; Y. Mizugaki
Proceedings of International Workshop on Modern Science and Technology, Tokyo, 66-71, Aug. 2012
International conference proceedings, English

Evaluation of Stacked Voltage Multiplier for Superconducting Josephson Digital-to-Analog Converter of Quantum Accuracy
Y. Sato; H. Shimada; Y. Mizugaki
Proceedings of International Workshop on Modern Science and Technology, Tokyo, 72-77, Aug. 2012
International conference proceedings, English

Average Voltage Measurements of Periodic Blocking Oscillation in Resistive Superconducting Quantum Interference Device Connected to Josephson Transmission Line
Yoshinao Mizugaki
JAPANESE JOURNAL OF APPLIED PHYSICS, JAPAN SOC APPLIED PHYSICS, 51, 3, 038001-1-2, Mar. 2012, Peer-reviwed, Blocking oscillation (BO) is a unique operation mode of resistive superconducting quantum interference devices (RSQUIDs). The author presents experimental measurements of periodic BO by means of the average voltage method. Test circuits are fabricated using a Nb/AlOx/Nb integration process. The input/output voltage ratio in an RSQUID, of which the output is connected to a Josephson transmission line (JTL), becomes 2 under appropriate operation conditions. Since the voltage ratio is exactly proportional to the input/output switching frequency ratio, the results demonstrate the periodic BO, in which the numbers of switching during one period are 2 and 1 in the input and output junction, respectively. (C) 2012 The Japan Society of Applied Physics
Scientific journal, English

Estimation of Nb Junction Temperature Raised Due to Thermal Heat from Bias Resistor
Keisuke Kuroiwa; Masaki Kadowaki; Masataka Moriya; Hiroshi Shimada; Yoshinao Mizugaki
IEICE TRANSACTIONS ON ELECTRONICS, IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG, E95C, 3, 355-359, Mar. 2012, Peer-reviwed, Superconducting integrated circuits should be operated at low temperature below a half of their critical temperatures. Thermal heat from a bias resistor could rise the temperature in Josephson junctions, and would reduce their critical currents. In this study, we estimate the temperature in a Josephson junction heated by a bias resistor at the bath temperature of 4.2 K, and introduce a parameter beta that connects the thermal heat from a bias resistor and the temperature elevation of a Josephson junction. By using beta, the temperature in the Josephson junction can be estimated as functions of the current through the resistor.
Scientific journal, English

Bipolar quantum voltage generator based on zero crossing Shapiro steps in asymmetric 2J-SQUIDs
Masataka Moriya; Naoki Kondo; Yoshinao Mizugaki
SUPERCONDUCTIVITY CENTENNIAL CONFERENCE 2011, ELSEVIER SCIENCE BV, 36, 235-238, 2012, On an asymmetric two-junction superconducting quantum interference device (2J-SQUID) driven by one sinusoidal rf signal, the observation of zero-crossing Shapiro steps have been reported. In this paper, the loop inductance, L and the ratio of critical currents of Josephson junctions of the 2J-SQUID were optimized by a simulation. Using three voltage states those this asymmetric 2J-SQUID has, the bipolar quantum voltage generator that has three asymmetric 2J-SQUIDs and two control lines, was designed based on obtained parameters. Within the bias current - voltage curves with seven different combinations of the control currents, seven quantized voltages were obtained at the zero bias current. (C) 2012 Published by Elsevier B.V. Selection and/or peer-review under responsibility of the Guest Editors.
International conference proceedings, English

Blocking Charge Oscillation in a Series Array of Two Tiny Tunnel Junctions with a Resistive Ground Path from Its Island Electrode
Yoshinao Mizugaki
IEEE TRANSACTIONS ON NANOTECHNOLOGY, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 11, 1, 194-199, Jan. 2012, Peer-reviwed, The author demonstrates blocking charge oscillation in a series array of two tiny tunnel junctions with an island electrode having a resistive ground path. In the array, single-electron tunneling carries electric charge discretely into the island, while charge leakage through the resistive path to the ground reduces the island charge continuously. The combination of the discrete and continuous charge transfer eventually results in blocking oscillation of the island charge. Numerical Monte Carlo simulation demonstrates the blocking oscillation. Bias conditions for the blocking oscillation are analytically derived.
Scientific journal, English

Blocking Oscillation Due to Combination of Discrete and Continuous Charge/Flux Transfer in Systems Including Nano/Josephson Tunnel Junctions
Yoshinao Mizugaki
PROCEEDINGS OF PROGRESS IN ELECTROMAGNETICS RESEARCH SYMPOSIUM (PIERS 2012), ELECTROMAGNETICS ACAD, 768-771, 2012, Peer-reviwed, Nanotechnology enables us to manipulate a single electron in solid-state circuits. Single-electron tunneling is known to transfer electric charge in units of the fundamental charge e through tiny (nano-scale) tunnel junctions. So far, many single-electron devices, such as a single-electron transistor, a single-electron turnstile, and a single-electron pump, have been proposed and demonstrated. The author proposes a blocking oscillator composed of tiny tunnel junctions and a dissipative element (resistor). The key is the combination of the discrete and continuous charge transfer. Monte-Carlo simulation demonstrates blocking oscillation of an island charge. Similar blocking oscillation occurs in a superconducting loop including Josephson junctions and a resistor. Electromagnetic duality between single-electron devices and superconducting Josephson devices are observed in these results. In this paper, the author numerically demonstrates these blocking oscillation phenomena and discuss the possibility of experimental observation.
International conference proceedings, English

Bipolar quantum voltage generator based on zero crossing Shapiro steps in asymmetric 2J-SQUIDs
Masataka Moriya; Naoki Kondo; Yoshinao Mizugaki
SUPERCONDUCTIVITY CENTENNIAL CONFERENCE 2011, ELSEVIER SCIENCE BV, 36, 235-238, 2012, Peer-reviwed, On an asymmetric two-junction superconducting quantum interference device (2J-SQUID) driven by one sinusoidal rf signal, the observation of zero-crossing Shapiro steps have been reported. In this paper, the loop inductance, L and the ratio of critical currents of Josephson junctions of the 2J-SQUID were optimized by a simulation. Using three voltage states those this asymmetric 2J-SQUID has, the bipolar quantum voltage generator that has three asymmetric 2J-SQUIDs and two control lines, was designed based on obtained parameters. Within the bias current - voltage curves with seven different combinations of the control currents, seven quantized voltages were obtained at the zero bias current. (C) 2012 Published by Elsevier B.V. Selection and/or peer-review under responsibility of the Guest Editors.
International conference proceedings, English

Design and Operation of 64-Fold Variable Single-Flux-Quantum Pulse-Number Multiplier
Yoshinao Mizugaki; Jun Saito; Masataka Moriya; Masaaki Maezawa
IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 21, 6, 3604-3607, Dec. 2011, Peer-reviwed, One of the unique applications of the single-flux-quantum (SFQ) circuitry is a digital-to-analog converter (DAC) with fundamental accuracy based on the Josephson effect. Recently, we have proposed a DAC based on frequency modulation of the output SFQ pulse train. A variable SFQ pulse-number multiplier (PNM) is a key component for the frequency-modulation DAC. In this paper, we report our design and test of a variable PNM in which the multiplication factor is determined by the sum of selected SFQ trains coming from a series array of toggle flip-flops. A 64-fold variable PNM is designed and tested using chips based on Nb. The low-speed test shows its correct functions of variable multiplication of one-to 64-fold. The high-speed test demonstrates the operation of output SFQ repetition frequency up to 0.82 GHz for 64-fold multiplication.
Scientific journal, English

Design and operation of voltage quadrupler cell for rapid-single-flux-quantum digital-to-analog converters
Y. Mizugaki; T. Tanaka; J. Saito; T. Kobayashi; M. Moriya; M. Maezawa
PHYSICA C-SUPERCONDUCTIVITY AND ITS APPLICATIONS, ELSEVIER SCIENCE BV, 471, 21-22, 1267-1269, Nov. 2011, Peer-reviwed, A conventional voltage multiplier cell in a rapid-single-flux-quantum (RSFQ) digital-to-analog converter is composed of an output dc-superconducting quantum interference device (dc-SQUID) magnetically coupled to an input Josephson transmission line. The authors previously demonstrated the operation of a voltage doubler cell that doubled the input voltage by introducing the second-mode operation. In this paper, we propose another type of a voltage multiplier cell, a voltage quadruplet, where the output dc-SQUID is replaced with two dc-SQUIDs sharing one coupling inductor. The proposed cell quadruples the input voltage when each SQUID is operated in the second-mode. A single voltage quadrupler has been designed and fabricated using the ISTEC standard process (STP2). Although operation margins for the bias current and the input SFQ repetition frequency are smaller than the values expected from simulation, its fundamental operation has been confirmed in experiment. (C) 2011 Elsevier B.V. All rights reserved.
Scientific journal, English

Design and functional tests of variable SFQ pulse number multiplier
J. Saito; T. Tanaka; M. Moriya; T. Kobayashi; Y. Mizugaki; M. Maezawa
PHYSICA C-SUPERCONDUCTIVITY AND ITS APPLICATIONS, ELSEVIER SCIENCE BV, 471, 21-22, 1270-1273, Nov. 2011, Peer-reviwed, For establishing a new generation of ac voltage standards, digital-to-analog converters (DACs) based on rapid single flux quantum (RSFQ) technology, which enable synthesis of arbitrary waveforms with fundamental accuracy, are developed. An RSFQ-DAC consists of three main subsystems: a pulse-number multiplier (PNM), a pulse distributor (PD) and voltage multipliers (VMs). Conventional RSFQ-DACs generate arbitrary voltages by switching a binary array of the VM cells. In this paper, we propose a Variable-PNM for a new RSFQ-DAC based on frequency modulation. The output voltage is determined by the multiplication factor m of the Variable-PNM that consists of a ring oscillator, an n-bit counter and a decoder. We designed a 2-bit Variable-PNM using the CONNECT cell library. The circuit was fabricated using the ISTEC Nb standard process (STP2). We have confirmed the correct functionalities for 2-, 4-, 6- and 8-fold multiplication in functional testing at low speed. (C) 2011 Elsevier B.V. All rights reserved.
Scientific journal, English

Quasi-Sine Waveform Synthesizer Based on SFQ Pulse-Frequency-Modulation
Y. Mizugaki; K. Kuroiwa; M. Moriya; H. Shimada; M. Maezawa
Proceedings of Superconducting SFQ VLSI Workshop (SSV 2011), 41-45, Nov. 2011
International conference proceedings, English

Operation of a Bipolar Quantum Voltage Generator Based on Zero-Crossing Shapiro Steps in Asymmetric 2J-SQUIDs
M. Moriya; N. Kondo; Y. Mizugaki
Abstracts of The 6th East Asia Symposium on Superconductor Electronics (EASSE 2011), 43, Oct. 2011
International conference proceedings, English

4-Step Quasi-Sine Waveform Synthesizer Based on 3-Bit Variable Pulse Number Multiplier
Y. Mizugaki; K. Kuroiwa; M. Moriya; H. Shimada; M. Maezawa
Abstracts of The 6th East Asia Symposium on Superconductor Electronics (EASSE 2011), 10, Oct. 2011
International conference proceedings, English

The Quantum Current Mirror based 10-time Current Multiplier
S. Gandrothula; Y. Mizugaki; H. Shimada
Supercnductivity Centennial Conference, A1061, Sep. 2011
International conference proceedings, English

Current Induction in Strongly Coupled Arrays of Small Josephson Junctions
H. Shimada; C. Ishida; Y. Mizugaki
11P-D034, Aug. 2011, Peer-reviwed
International conference proceedings, English

Evaluation of Two Methods for Suppressing Ground Current in the Superconducting Integrated Circuits
Keisuke Kuroiwa; Masataka Moriya; Tadayuki Kobayashi; Yoshinao Mizugaki
IEICE TRANSACTIONS ON ELECTRONICS, IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG, E94C, 3, 296-300, Mar. 2011, Peer-reviwed, Although larger scale integration enhances the practicability of superconducting Josephson circuits, several technical problems begin to emerge during its progress. One of the problems is the increase of current through a ground plane (ground current). Excess ground current produces additional magnetic field and reduces operation margins of the circuits, because superconducting Josephson devices are very sensitive to magnetic field. In this paper, we evaluate current distribution in a superconducting ground plane by means of both experiments and numerical calculation. We also verify two methods for suppressing the ground current. One is a slot structure in the ground plane, and the other is alignment of the current-extraction point. Suppression of the ground current is quantitatively evaluated.
Scientific journal, English

Design and operation of voltage quadrupler cell for rapid-single-flux-quantum digital-to-analog converters
Y. Mizugaki; T. Tanaka; J. Saito; T. Kobayashi; M. Moriya; M. Maezawa
Program and Abstracts of 23rd International Symposium on Superconductivity, 145, Nov. 2010
International conference proceedings, English

High- and low-speed tests of variable SFQ pulse number multiplier
J. Saito; T. Tanaka; M. Moriya; T. Kobayashi; Y. Mizugaki; M. Maezawa
Program and Abstracts of 23rd International Symposium on Superconductivity, 301, Nov. 2010
International conference proceedings, English

Numerical Demonstration of Relaxation Oscillation in a Resistive Superconducting Quantum Interference Device With Two Nonhysteretic Josephson Junctions
Yoshinao Mizugaki
IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 20, 5, 2322-2326, Oct. 2010, Peer-reviwed, The author numerically demonstrates that a resistive superconducting quantum interference device (RSQUID) with two nonhysteretic Josephson junctions works as a relaxation oscillator. Sequential switching of the Josephson junctions transfers positive and negative flux quanta in the RSQUID loop one by one. Differently from a conventional two-junction superconducting quantum interference device, the dissipative RSQUID loop does not maintain the quantized flux, and hence, finite flux can be accumulated in the RSQUID loop during sequential switching of the Josephson junctions. When the accumulated flux reaches a critical value, the corresponding loop current prevents subsequent junction switching. That is, the oscillation stops. After the loop current decays, sequential switching of the junctions resumes. In addition to the waveforms of relaxation oscillation, dependence of relaxation oscillation on device parameters is presented.
Scientific journal, English

Relaxation Oscillation in Single-Electron Transistor with Resistively-Shunted Gate
Y. Mizugaki
Proceedings of 2010 International Symposium on Nonlinear Theory and its Applications (NOLTA 2010), 43-46, Sep. 2010, Peer-reviwed
International conference proceedings, English

Analytical Inductance Calculation of Superconducting Stripline by Use of Transformation into Perfect Conductor Model
Yoshinao Mizugaki; Akio Kawai; Ryuta Kashiwa; Masataka Moriya; Tadayuki Kobayashi
IEICE TRANSACTIONS ON ELECTRONICS, IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG, E93C, 4, 486-488, Apr. 2010, Peer-reviwed, We present analytical expression for inductance of a superconducting stripline, a strip sandwiched by two superconducting ground planes In our method, we utilize the analytical formula for a perfect-conducting stripline derived by Chang in 1976 To utilize Chang's formula. we first transform the structure of a superconducting stripline into that of a perfect-conducting stripline by reducing the thicknesses of the superconducting layers The thickness reduction is "lambda coth(t/lambda)' tor each (upper or lower) side. where lambda and t are the field penetration depth and the layer thickness. respectively Then. we apply Chang's formula to the transformed stripline model The calculated results are in good agreement with the numerical and experimental results
Scientific journal, English

Mutual coupling between two superconducting strip lines horizontally-placed in niobium integrated chips
Yoshinao Mizugaki; Akio Kawai; Ryuta Kashiwa; Masataka Moriya; Tadayuki Kobayashi
9TH EUROPEAN CONFERENCE ON APPLIED SUPERCONDUCTIVITY (EUCAS 09), IOP PUBLISHING LTD, 234, 332, 2010, We evaluate mutual inductance between two horizontally-placed strip lines in niobium integrated chips, by means of both experiments and numerical calculations. In the experiments, one strip line is used as a part of a superconducting quantum interference device (SQUID) loop, and the other is used as a control line for applying external magnetic flux to the SQUID loop. The mutual inductance is obtained from the modulation period of the SQUID. In the numerical calculations, we employ a three-dimensional inductance extraction software (FastHenry). Three types of strip line structures on a lower ground plane (GP) are examined: two horizontally-placed microstrip lines without an upper GP (MSLs), two horizontally-placed strip lines with a floating upper GP (FLSLs), and two strip lines with an upper GP connected to the lower GP (COSLs). We have found that each strip line structure has different dependence of mutual inductance on the line center distance. The mutual inductance between the MSLs exhibits strong dependence on the line center distance, whereas that between FLSLs is almost independent on the distance. Negligible mutual inductance is obtained for the COSLs.
International conference proceedings, English

Design and Operation of the Voltage Multiplier Cell with a Stacked-SQUID
T. Tanaka; J. Saito; T.i Kobayashi; M. Moriya; Y. Mizugaki; M. Maezawa
Proceedings of Superconducting SFQ VLSI Workshop (SSV 2010), 41-44, Jan. 2010
International conference proceedings, English

Design and Evaluation of Stripline Inductances in Superconducting Multilayer Integrated Circuits
Y. Mizugaki; M. Moriya; T. Kobayashi
Proceedings of Superconducting SFQ VLSI Workshop (SSV 2010), 25-30, Jan. 2010
International conference proceedings, English

Mutual coupling between two superconducting strip lines horizontally-placed in niobium integrated chips
Yoshinao Mizugaki; Akio Kawai; Ryuta Kashiwa; Masataka Moriya; Tadayuki Kobayashi
9TH EUROPEAN CONFERENCE ON APPLIED SUPERCONDUCTIVITY (EUCAS 09), IOP PUBLISHING LTD, 234, 4, 042021-1-5, 2010, Peer-reviwed, We evaluate mutual inductance between two horizontally-placed strip lines in niobium integrated chips, by means of both experiments and numerical calculations. In the experiments, one strip line is used as a part of a superconducting quantum interference device (SQUID) loop, and the other is used as a control line for applying external magnetic flux to the SQUID loop. The mutual inductance is obtained from the modulation period of the SQUID. In the numerical calculations, we employ a three-dimensional inductance extraction software (FastHenry). Three types of strip line structures on a lower ground plane (GP) are examined: two horizontally-placed microstrip lines without an upper GP (MSLs), two horizontally-placed strip lines with a floating upper GP (FLSLs), and two strip lines with an upper GP connected to the lower GP (COSLs). We have found that each strip line structure has different dependence of mutual inductance on the line center distance. The mutual inductance between the MSLs exhibits strong dependence on the line center distance, whereas that between FLSLs is almost independent on the distance. Negligible mutual inductance is obtained for the COSLs.
International conference proceedings, English

ニオブ集積回路における平行線路間の相互インダクタンス評価
河合章生; 柏竜太; 守屋雅隆; 小林忠行; 水柿義直
電子情報通信学会論文誌, The Institute of Electronics, Information and Communication Engineers, J92-C, 9, 523-530, Sep. 2009, Peer-reviwed, 我々は,同一の配線層に形成された平行線路間の相互インダクタンスについて,テスト回路による実験と数値計算による評価を行った.実験には,SRLニオブ標準プロセスを用いて作製したテスト回路を使用した.数値計算には,三次元インダクタンス抽出プログラム"FastHenry"を使用した.評価した回路は上部グランドプレーン(GP)の有無と上部下部GP間の接地の有無により3種類の構造に分けられる.線路構造の違いにより相互インダクタンスの線路中心間距離に対する依存性が異なることが明らかとなった.これについては,伝送線路内の電流・磁場強度分布の違いにより説明できた.また,接地を行わないストリップライン構造において,上部GP幅が大きいほど相互インダクタンスが減少することが分かった.更に,接地を行ったストリップライン構造において,上部下部GP間の接地点がSQUIDのJJ-下部GP間の接地点の近傍であるとき,相互インダクタンスが極小となることが分かった.
Scientific journal, Japanese

ホットエレクトロン効果を考慮した微小トンネル接合2次元アレイの微分コンダクタンス特性
田村伸行; 滝口将志; 島田宏; 水柿義直
電子情報通信学会論文誌, The Institute of Electronics, Information and Communication Engineers, J92-C, 9, 534-536, Sep. 2009, Peer-reviwed, ホットエレクトロン効果を考慮した微小トンネル接合二次元アレーの特性式を提案し,実験結果とのフィッティングを行ったところ良い一致が得られた.
Scientific journal, Japanese

Magnetic Isolation Enhanced by a Superconducting Loop in Josephson Integrated Circuits
Yoshinao Mizugaki; Ryuta Kashiwa; Akio Kawai; Masataka Moriya; Kouichi Usami; Tadayuki Kobayashi
JAPANESE JOURNAL OF APPLIED PHYSICS, JAPAN SOCIETY APPLIED PHYSICS, 48, 7, 073001-1-5, Jul. 2009, Peer-reviwed, Mutual inductance between two superconducting strip lines coupled through a grounded shield layer is evaluated by both experiments and numerical calculation. A conventional superconducting quantum interference device (SQUID) method on a Nb Josephson IC chip is employed for experiments, whereas a three-dimensional inductance extraction program "FastHenry" is used in numerical calculation. Five test circuits are designed to investigate the effects of two ground contacts placed parallel to the strip lines with different spacing. Both the experimental and numerical results confirm that the mutual inductance is at its minimum when the contacts are placed close to the Josephson junctions, that is, the edges of the SQUID line under evaluation. In the experiments, the minimum value of the mutual inductance is 26% of the value for the reference circuit with a floating shield layer. A model including the Meissner effect in a superconducting loop is found to provide a quasi-quantitative explanation for the dependence on the spacing between two contacts. (C) 2009 The Japan Society of Applied Physics DOI: 10.1143/JJAP.48.073001
Scientific journal, English

Magnetic isolation enhanced by the Meissner effect of a superconducting loop in multi-layered Nb integrated circuits
Y. Mizugaki; R. Kashiwa; A. Kawai; M. Moriya; T. Kobayashi
Proceedings of Superconducting SFQ VLSI Workshop (SSV 2009), 9-10, Jun. 2009
International conference proceedings, English

Mutual Inductance between Two Strip Lines Sandwiched by Two Ground Planes
Y. Mizugaki; A. Kawai; R. Kashiwa; M. Moriya; T. Kobayashi
Proceedings of Superconducting SFQ VLSI Workshop (SSV 2009), 41-42, Jun. 2009
International conference proceedings, English

Fabrication and properties of the variable thickness bridges with YBCO thin film
M. Moriya; A. Hashimoto; Y. Mizugaki; T. Kobayashi
Extended Abstracts of the 12th International Superconductive Electronics Conference 2009 (ISEC 2009), TD-P15, Jun. 2009
International conference proceedings, English

Stacked-SQUID-based Voltage Multiplier Cell Generating Twofold or Fourfold Voltage
T. Tanaka; T. Kobayashi; M. Moriya; Y. Mizugaki; M. Maezawa
Extended Abstracts of the 12th International Superconductive Electronics Conference 2009 (ISEC 2009), SP-P22, Jun. 2009
International conference proceedings, English

Design and Operation of 2$^n$-fold Variable SFQ Pulse Number Multiplier
J. Saito; R. Kashiwa; A. Kawai; T. Tanaka; M. Moriya; T. Kobayashi; Y. Mizugaki; M. Maezawa
Extended Abstracts of the 12th International Superconductive Electronics Conference 2009 (ISEC 2009), SP-P23, Jun. 2009
International conference proceedings, English

Analytical Calculation for Inductance of Superconducting Stripline
Y. Mizugaki; A. Kawai; R. Kashiwa; M. Moriya; T. Kobayashi
Extended Abstracts of the 12th International Superconductive Electronics Conference 2009 (ISEC 2009), SP-P38, Jun. 2009
International conference proceedings, English

Current Doublers Based on the Quantum Current-Mirror Effect
Hiroshi Shimada; Sumio Hanadou; Takuma Kawa; Hiroto Kido; Yoshinao Mizugaki
JAPANESE JOURNAL OF APPLIED PHYSICS, JAPAN SOCIETY APPLIED PHYSICS, 47, 10, 8131-8136, Oct. 2008, Peer-reviwed, Two types of current doublers, which operate in a sub-nanoampere range, have been fabricated as prototypes of a precise current multiplier for metrological application. The current doubling function of the devices is based on the quantum current-mirror effect in coupled arrays of small Josephson junctions. Both types of devices comprise three arrays of small Josephson junctions: the first device has two serial short arrays coupled to one long array, and the second device has three arrays of the same size arranged in parallel. The arrays for the current input are the long array in the first device and one of the three arrays in the second device, and a parallel connection of the other two arrays in each device forms the output port. In both types of devices, a current fed to the input array is doubled in the output circuit, which includes the connected arrays, up to about 100pA with the accuracy <=+/- 3pA, which is the uncertainty of the measurement system, by correlated tunnelings of Cooper-pair charge solitons in the arrays. The feasibility of producing a current Multiplier has been ascertained on the basis of this effect. [DOI: 10.1143/JJAP.47.8131]
Scientific journal, English

Single-Electron Devices With Input Discretizer
Yoshinao Mizugaki; Masashi Takiguchi; Shota Hayami; Akio Kawai; Masataka Moriya; Kouichi Usami; Tadayuki Kobayashi; Hiroshi Shimada
IEEE TRANSACTIONS ON NANOTECHNOLOGY, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 7, 5, 601-606, Sep. 2008, Peer-reviwed, We propose an input discretizer for single-electron (SE) devices. The input discretizer is composed of one small tunnel junction and two capacitances. Adjusting the capacitances to be equal discretizes the gate charge with interval of a half of the elementary charge e, which enhances the performance of SE devices. An SE transistor with the input discretizer has abrupt switchings of the Coulomb blockade thresholds, resulting in steep responses to the input signal. An SE turnstile with the input discretizer enhances its operation margins for the application of a digital-to-analog converter element. Both analytical and numerical results are presented.
Scientific journal, English

Current Multipliers Based on the Quantum Current Mirror
H. Shimada; S. Hanadou; T. Kawai; H. Kido; Y. Mizugaki
25th International Conference on Low Temperature Physics (LT25), PD-Mo284, Aug. 2008, Peer-reviwed
International conference proceedings, English

Self-organized microcones grown on Si substrate by microwave plasma chemical vapor deposition
Masataka Moriya; Yuji Matsumoto; Yoshinao Mizugaki; Tadayuki Kobayashi; Kouichi Usami
JAPANESE JOURNAL OF APPLIED PHYSICS, JAPAN SOCIETY APPLIED PHYSICS, 47, 4, 3050-3052, Apr. 2008, Peer-reviwed, Self-organized microcones were grown on an n-Si(100) substrate by microwave plasma chemical vapor deposition. It was found that microcones having a cross section of an isosceles triangle were successfully grown on the Si substrate and that all the microcones had almost the same sizes. From the results of X-ray photoelectron spectroscopy (XPS), we concluded that the microcones consist of SiC covered with a thin carbon-based material. A model of the growth mechanism of the microcones was derived assuming that thermally assisted field emission and bombardment with ions accelerated by an electric field in the ion sheath of microwave plasma play an important role in the growth of the microcones. The field dependence of emission current from the microcones in vacuum agreed with the Fowler-Nordheim model, which indicates that these microcones can be used as field emission arrays.
Scientific journal, English

Inductance of Superconducting Stripline Sandwiched between Two Ground Planes
Y. Mizugaki; R. Kashiwa; A. Kawai; M. Moriya; T. Kobayashi
Proceedings of Superconducting SFQ VLSI Workshop (SSV 2008), 33-35, Mar. 2008
International conference proceedings, English

Magnetic Shielding Effect of Grounded Superconducting Niobium Layers
Yoshinao Mizugaki; Ryuta Kashiwa
8TH EUROPEAN CONFERENCE ON APPLIED SUPERCONDUCTIVITY (EUCAS'07), IOP PUBLISHING LTD, 97, 83, 2008, Peer-reviwed, Magnetic isolation is an important issue in the realization of superconducting LSIs including more than ten thousands Josephson junctions. In this paper, we present mutual inductances of two superconducting strip lines coupled through a grounded shield layer. A conventional dc-superconducting quantum interference device (dc-SQUID) method on Nb/AlO(x)/Nb Josephson IC chips is employed. We have tested one dc-SQUID layout with a floating shield layer for reference, and ten dc-SQUID layouts with grounded shield layers. Four superconducting niobium layers are used as a ground plane, a SQUID line, a shield layer, and a control line from bottom to top. We have confirmed that the number, positions, and dimensions of ground contacts make differences in the mutual inductances. Ground contacts should be placed to enhance the shielding current for effective magnetic isolation.
International conference proceedings, English

Magnetic Shielding Effect of Grounded Superconducting Niobium Layers
Yoshinao Mizugaki; Ryuta Kashiwa
8TH EUROPEAN CONFERENCE ON APPLIED SUPERCONDUCTIVITY (EUCAS'07), IOP PUBLISHING LTD, 97, 012056-1-5, 2008, Peer-reviwed, Magnetic isolation is an important issue in the realization of superconducting LSIs including more than ten thousands Josephson junctions. In this paper, we present mutual inductances of two superconducting strip lines coupled through a grounded shield layer. A conventional dc-superconducting quantum interference device (dc-SQUID) method on Nb/AlO(x)/Nb Josephson IC chips is employed. We have tested one dc-SQUID layout with a floating shield layer for reference, and ten dc-SQUID layouts with grounded shield layers. Four superconducting niobium layers are used as a ground plane, a SQUID line, a shield layer, and a control line from bottom to top. We have confirmed that the number, positions, and dimensions of ground contacts make differences in the mutual inductances. Ground contacts should be placed to enhance the shielding current for effective magnetic isolation.
International conference proceedings, English

Precise dc-current duplication and multiplication with arrays of small Josephson junctions
H. Shimada; S. Hanadou; Y. Mizugaki
International Symposium on Coherent Optical Science, 38, Dec. 2007
International conference proceedings, English

Tunnel magnetoresistance in ferromagnet-superconductor-ferromagnet single-electron transistors with different lead Spacings up to 50 mu m
Yoshinao Mizugaki; Hidemitsu Hakii; Masataka Moriya; Kouichi Usami; Tadayuki Kobayashi; Hiroshi Shimada
JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS & EXPRESS LETTERS, INST PURE APPLIED PHYSICS, 46, 36-40, L901-L903, Oct. 2007, Peer-reviwed, We fabricated single-electron transistors (SETs) with ferromagnetic (FM) Co leads and superconducting (SC) Al islands, and measured their tunnel magnetoresistances. Under the antiparallel magnetization state of the two FM leads, current increase due to the SC gap suppression by spin accumulation was observed. Tunnel magnetoresistance ratios of the antiparallel state to the parallel state were investigated for 10 FM SETs with different spacings between the two FM leads, from 0.35 to 50 mu m. Spin valve effects were confirmed in the SETs with an FM lead spacing not only on the submicron order but also of 50 mu m.
Scientific journal, English

Design and operation of a series array of voltage doubler cells for rapid-single-flux-quantum digital-to-analog converters
Yoshinao Mizugaki; Yoko Namatame; Masaaki Maezawa
Superconductor Science and Technology, {IOP} Publishing, 20, 11, S315-S317, Oct. 2007, Peer-reviwed
Scientific journal, English

Current correlation in single-electron current mirror electromagnetically dual to Josephson voltage mirror
Yoshinao Mizugaki; Masafumi Itoh; Hiroshi Shimada
JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS BRIEF COMMUNICATIONS & REVIEW PAPERS, INST PURE APPLIED PHYSICS, 46, 9B, 6237-6242, Sep. 2007, Peer-reviwed, The electromagnetic duality between single-electron devices and Josephson devices sometimes helps us to develop new electron devices. In this article, a single-electron turnstile is discussed as a dual device to a de superconducting quantum interference device (dc-SQUID). From the viewpoint of the device characteristics, a,single-electron turnstile has better duality to a dc-SQUID than a single-electron transistor. Next, a current mirror based on single-electron turnstiles is introduced as a dual circuit corresponding to a Josephson voltage mirror. A test circuit of a current mirror was fabricated using electron beam lithography and aluminum shadow evaporation. Although the precise current mirror operation was not obtained, we observed two currents approaching each other. Simulation based on the Monte Carlo method succeeded in reproducing the experimental results. Numerical results indicate that insufficient capacitive coupling, nonnegligible parasitic capacitances, and short array length deteriorate the current mirror operation.
Scientific journal, English

Self organized Micro Cones on Si substrate by Microwave Plasma Chemical Vapor Deposition
M. Moriya; Y. Matsumoto; Y. Mizugaki; T. Kobayashi; K. Usami
Extended abstracts of the 2007 International Conference on Solid State Devices and Materials, 560-561, Sep. 2007, Peer-reviwed
International conference proceedings, English

Optimization of asymmetric single-electron transistor generating ac-induced dc current
Yoshinao Mizugakia; Akio Kawai; Masataka Moriya; Kouichi Usami; Tadayuki Kobayashi; Hiroshi Shimada
IEICE ELECTRONICS EXPRESS, IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG, 4, 11, 345-350, Jun. 2007, Peer-reviwed, Charge tunneling events in an ac-voltage-driven asymmetric single-electron transistor (aSET) under appropriate gate charge are rectified due to the tilted Coulomb blockade (CB) diagram, which induces finite dc electric current even under zero dc biasing. We demonstrate dependence of the dc current upon the gate charge and the amplitude of the ac voltage by means of numerical simulation based on the Monte Carlo method. Device parameters of the aSET optimized for generation of the ac-induced dc current are derived by both analytical and numerical methods.
Scientific journal, English

Grounding positions of superconducting layer for effective magnetic isolation in Josephson integrated circuits
Yoshinao Mizugaki; Ryuta Kashiwa; Masataka Moriya; Kouichi Usami; Tadayuki Kobayashi
JOURNAL OF APPLIED PHYSICS, AMER INST PHYSICS, 101, 11, 114509-1-4, Jun. 2007, Peer-reviwed, Mutual inductances between two superconducting strip lines coupled through a grounded shield layer are evaluated by both experiments and numerical calculation. A conventional superconducting quantum interference device method on a Nb Josephson integrated circuit chip is employed for experiments. Four test circuits are designed to investigate the effects of ground contacts. Grounding the shield layer at one point or at two points located perpendicular to the line direction does not improve the shielding effect, whereas grounding at two points located parallel to the line direction reduced the mutual inductance by 67%. Mutual inductances calculated using an inductance extraction program, FASTHENRY, agree with the experimental results. Numerical results of current distributions in the shield layers demonstrate that the enhanced shielding current improves the magnetic isolation. (c) 2007 American Institute of Physics.
Scientific journal, English

A Voltage Doubler Based on the Second-Order Operation of a Voltage Multiplier Cell
Y. Mizugaki; Y. Namatame; M. Maezawa
Conference Program and Extended Abstracts of the 11th International Supserconductive Electronics Conference, O-J02, Jun. 2007
International conference proceedings, English

Current multiplication based on the quantum current-mirror effect
Hiroshi Shimada; Takuma Kawai; Yoshinao Mizugaki
IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 17, 2, 602-604, Jun. 2007, Peer-reviwed, A small-current doubler has been fabricated that utilizes the quantum current-mirror effect in capacitively coupled arrays of mesoscopic Josephson junctions. The device showed expected doubler behavior for currents in the 10 picoampere range. The feasibility of producing a current multiplier that is based on this effect has been ascertained.
Scientific journal, English

Coulomb blockade conditions for detailed model of single-electron turnstile device including finite self-capacitances of island electrodes
Asaki Mizuta; Masataka Moriya; Kouichi Usami; Tadayuki Kobayashi; Hiroshi Shimada; Yoshinao Mizugaki
JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS BRIEF COMMUNICATIONS & REVIEW PAPERS, INST PURE APPLIED PHYSICS, 46, 5A, 3144-3148, May 2007, Peer-reviwed, We propose a detailed model of a single-electron turnstile device in which each island electrode has a finite self-capacitance. The Coulomb blockade (CB) regions are obtained by calculating the free energy of the system, and are graphically presented in the gate-charge versus bias-voltage plane. We confirm the CB regions obtained to be octagonal, instead of the quadrilateral CB regions obtained in the conventional model.
Scientific journal, English

Voltage Doubler Cell for Rapid Single Flux Quantum Digital-to-Analog Converter
Yoko Namatame; Masaaki Maezawa; Masataka Moriya; Kouichi Usami; Tadayuki Kobayashi; Yoshinao Mizugaki
Japanese Journal of Applied Physics, {IOP} Publishing, 46, No. 18, L430-L432, Apr. 2007, Peer-reviwed
Scientific journal, English

Zero-crossing Shapiro step generated in an asymmetric and nonhysteretic rf-current-driven two-junction superconducting quantum interference device
Yoshinao Mizugaki; Kazuyuki Katoh
JOURNAL OF APPLIED PHYSICS, AMER INST PHYSICS, 100, 6, 064503-1-064503-4, Sep. 2006, Peer-reviwed, A zero-crossing Shapiro step (ZCSS) in an asymmetric and nonhysteretic two-junction superconducting quantum interference device (SQUID) driven by one sinusoidal rf signal is presented. The operation is based on imbalanced evolution of the junction phases owing to the tilted interference diagrams. Dependence of ZCSS generation upon the frequency and amplitude of a rf signal was numerically obtained. A test circuit was designed and fabricated using a Nb/AlOx/Nb junction technology. When we irradiated a rf signal of 10 GHz, a ZCSS at the voltage position of the first order was observed. The polarity of the step voltage was switched by a dc control flux to the SQUID loop. The experimental bias-current versus voltage and control-current versus voltage curves were quantitatively reproduced by numerical simulation. (c) 2006 American Institute of Physics.
Scientific journal, English

Zero-crossing shapiro step in asymmetric two-junction superconducting quantum interference device
Yoshinao Mizugaki; Kazuyuki Katoh; Masataka Moriya; Kouichi Usami; Tadayuki Kobayashi
Japanese Journal of Applied Physics, Part 2: Letters, 45, 24-28, L621-L622, 16 Jun. 2006, Peer-reviwed, We demonstrate a zero-crossing Shapiro step in an asymmetric two-junction superconducting quantum interference device (SQUID) driven by one sinusoidal RF signal. The operation is based on the imbalanced evolution of the junction phases due to the tilted interference diagrams. A test circuit was fabricated using Nb/AlOx/Nb junction technology. When we applied an RF signal of 10 GHz, we observed a Shapiro step crossing the zero-current axis at the voltage position of the first order. The polarity of the step voltage was switched by a DC control flux to the SQUID loop. The experimental current-voltage curves were quantitatively reproduced by simulation. © 2006 The Japan Society of Applied Physics.
Scientific journal, English

Two-Dimensional Array of Nanotubes Grown in Porous Anodic Alumina by Ethanol Electrolysis
Yoshinao Mizugaki; Kyohei Kobayashi; Masataka Moriya; Kouichi Usami; Tadayuki Kobayashi
Japanese Journal of Applied Physics, {IOP} Publishing, 45, No. 25, L657-L658, Jun. 2006, Peer-reviwed
Scientific journal, English

Numerical and experimental evaluation of mutual inductances between two superconducting striplines coupled through a superconducting intermediate layer
Yoshinao Mizugaki; Hidemitsu Hakii; Masataka Moriya; Kouichi Usami; Tadayuki Kobayashi
IEICE ELECTRONICS EXPRESS, IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG, 3, 4, 64-69, Feb. 2006, Peer-reviwed, We evaluated mutual inductances between two superconducting striplines coupled through a superconducting intermediate layer in Nb Josephson IC. In order to measure the mutual inductances we designed eight test circuits based on a superconducting quantum interference device (SQUID), which included intermediate layers of two different thicknesses and four different widths. The inductance extraction program FastHenry with superconductor support was used for numerical calculation. The experimental results agreed with the calculated results, both of which confirmed that a thicker and wider intermediate layer reduced the mutual coupling more efficiently.
Scientific journal, English

Current-step-like structure in a YBCO grain boundary Josephson junction coupled to a gigahertz signal
Yoshinao Mizugaki; Jian Chen
7TH EUROPEAN CONFERENCE ON APPLIED SUPERCONDUCTIVITY (EUCAS'05), IOP PUBLISHING LTD, 43, 1282-1285, 2006, We demonstrate current-step-like structures observed in a YBa2Cu3O7-delta (YBCO) grain boundary Josephson junction (GBJJ) coupled to a gigahertz (GHz) signal. It is well known that a microwave-current-driven Josephson junction does not exhibit clear Shapiro steps under a low frequency condition of f << IcRn/Phi(0), where f, I-c, R-n, and Phi(0) are the microwave frequency, the critical current of the junction, the normal resistance of the junction, and a flux quantum, respectively. Instead of Shapiro steps, however, we often observe an anomalous upturn in the current-voltage curve of YBCO GBJJ's coupled to a GHz signal. We refer to the upturn as a current-step-like structure. Numerical analysis using an rf-field-driven two-junction superconducting quantum interference device ( SQUID) model indicates that the envelope of small Shapiro steps, including the effects of microwave-induced motion of flux quanta, appears as a current-step-like structure.
International conference proceedings, English

Current-step-like structure in a YBCO grain boundary Josephson junction coupled to a gigahertz signal
Yoshinao Mizugaki; Jian Chen
7TH EUROPEAN CONFERENCE ON APPLIED SUPERCONDUCTIVITY (EUCAS'05), IOP PUBLISHING LTD, 43, 1282-1285, 2006, Peer-reviwed, We demonstrate current-step-like structures observed in a YBa2Cu3O7-delta (YBCO) grain boundary Josephson junction (GBJJ) coupled to a gigahertz (GHz) signal. It is well known that a microwave-current-driven Josephson junction does not exhibit clear Shapiro steps under a low frequency condition of f << IcRn/Phi(0), where f, I-c, R-n, and Phi(0) are the microwave frequency, the critical current of the junction, the normal resistance of the junction, and a flux quantum, respectively. Instead of Shapiro steps, however, we often observe an anomalous upturn in the current-voltage curve of YBCO GBJJ's coupled to a GHz signal. We refer to the upturn as a current-step-like structure. Numerical analysis using an rf-field-driven two-junction superconducting quantum interference device ( SQUID) model indicates that the envelope of small Shapiro steps, including the effects of microwave-induced motion of flux quanta, appears as a current-step-like structure.
International conference proceedings, English

Quantum Electric-Current Mirrors Based on Small Tunnel-Junction Systems
M. Itoh; T. Kawai; Y. Mizugaki; H. Shimada
International Symposium on Coherent Optical Science, PS5, Jul. 2005
International conference proceedings, English

Monte Carlo study of charge transport in slantingly coupled arrays of small tunnel junctions
Y Mizugaki; H Shimada
PHYSICAL REVIEW B, AMERICAN PHYSICAL SOC, 71, 11, 115130-1-7, Mar. 2005, Peer-reviwed, We present a numerical investigation on the charge transport in capacitively coupled arrays of small tunnel junctions in the case of slanted coupling. Current-voltage characteristics of the arrays having various coupling capacitance (C-c) are simulated using the Monte Carlo method. In contrast to the case of straight coupled arrays, slantingly coupled arrays exhibit the current mirror effect using a coupling capacitance as small as C-c/C similar or equal to 0.1, where C is the junction capacitance. However, when C-c is too large (C-c/C>1), electron-electron or hole-hole chains are formed in each array, which deteriorate the current mirror effect. Conditions for the formation of such chains are derived from analysis of a simplified model of slantingly coupled arrays.
Scientific journal, English

Model analysis for a current-step-like structure in a high T-c Josephson device coupled to a microwave signal
Y Mizugaki; J Chen
JOURNAL OF APPLIED PHYSICS, AMER INST PHYSICS, 97, 6, 063906-1-5, Mar. 2005, Peer-reviwed, High T-c Josephson junctions have IcRn products as large as a few mV at liquid helium temperature, and hence, the frequency normalized by IcRn/Phi(0) becomes on the order of 10(-3) for a gigahertz (GHz) microwave signal. (Here, I-c, R-n, and Phi(0) are the critical current, the normal resistance, and a flux quantum, respectively.) It is well known that a microwave-current-driven Josephson junction does not exhibit clear Shapiro steps under such low frequency conditions. Instead of Shapiro steps, however, we often observe a current-step-like structure in the current-voltage curve of YBa2Cu3O7-delta grain boundary Josephson junctions coupled to a GHz signal. In this article, we present a model analysis for such current-step-like structures. Two types of device models are employed: a simple resistively and capacitively shunted junction model and a rf-field-driven two-junction superconducting quantum interference device model. Numerical results of the latter model agree with the experimental results, which indicates that the envelope of small Shapiro steps, including the effects of microwave-induced motion of flux quanta, appears as a current-step-like structure in a high T-c Josephson device coupled to a GHz microwave. (C) 2005 American Institute of Physics.
Scientific journal, English

Numerical analysis of a SQUID model for high-Tc Josephson junctions coupled with RF magnetic signals
Y. Mizugaki; J. Chen
Proceedings of 2005 Japan-Taiwan Symposium on Superconductive Electronics, The Institute of Electronics, Information and Communication Engineers, 104, 654, 9-12, Feb. 2005, Numerically-simulated properties of an RF-field-driven SQUID (superconducting quantum interference device) model are presented. In the model, an RF signal is coupled with the SQUID loop magnetically. By comparison with the results of the conventional RF-current-driven junction model in literature, simulated RF responses of the RF-field-driven SQUID model exhibit enhanced nonlinearity (e.g., larger Shapiro steps) for a wider frequency range. Two anomalous experimental results of YBa_2Cu_3O_<7-δ> grain boundary Josephson junctions are numerically reproduced by using the RF-field-driven SQUID model. The one is the magnetically-enhanced Shapiro steps under THz signal irradiation, and the other is the step-like-structure under GHz signal irradiation.
International conference proceedings, English

Mutual inductance coupled through superconducting thin film in niobium Josephson integrated circuits
Y Mizugaki; H Hakii; M Moriya; K Usami; T Kobayashi
JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS & EXPRESS LETTERS, INST PURE APPLIED PHYSICS, 44, 24-27, L763-L765, 2005, Peer-reviwed, We present numerical and experimental investigation on mutual inductance coupled through a superconducting Nb thin film. The inductance extraction program FASTHENRY with superconductor support is used for numerical calculation. The self- and mutual inductances of two superconducting strip lines are calculated as functions of the width of the shield layer inserted between them. The results demonstrate that the mutual coupling is reduced with increasing shield layer width. A superconducting quantum interference method is employed to measure the mutual inductance on Nb IC chips. The experimental results of the mutual inductance agree with the calculated results.
Scientific journal, English

3接合SQUIDの単一磁束量子ポンプ動作と単一電子デバイスとの双対性
水柿義直
Oyo Buturi, 応用物理学会, 73, 1, 41-44, Jan. 2004, Peer-reviwed
Scientific journal, Japanese

Differential conductance properties of La2-xSrCUO4 intrinsic Josephson junctions under magnetic field
Y Mizugaki; Y Uematsu; K Nakajima; T Yamashita; S Watauchi; Tanaka, I
JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS SHORT NOTES & REVIEW PAPERS, INST PURE APPLIED PHYSICS, 43, 1, 124-125, Jan. 2004, Peer-reviwed, We investigated differential conductance properties of c-axis microbridges fabricated in La2-xSrxCuO4 (LSCO) single crystals. Periodic conductance peaks were observed in both overdoped and underdoped LSCO samples. We applied a magnetic field parallel to the ab-plane and examined the behaviors of differential conductance properties (DCPs). The DCP of the overdoped sample was little affected by magnetic fields up to 4 T, whereas that of the underdoped sample exhibited strong dependence on the magnetic field.
Scientific journal, English

単電子帯電効果のデバイス応用とジョセフソンデバイスとの双対性
水柿義直
東北大学電気通信研究所 平成15年度工学研究会（通研講演会）, Dec. 2003
Japanese

Numerical investigation for the frequency dependence of Shapiro steps in an RF-field-driven SQUID
Y. Mizugaki
Superconductor Science and Technology, 16, 12, 1380-1382, Nov. 2003, Peer-reviwed
Scientific journal, English

Numerical investigation on the current mirror effect in a single-electron turnstile capacitively coupled to a one-dimensional array of small junctions
Y Mizugaki
JOURNAL OF APPLIED PHYSICS, AMER INST PHYSICS, 94, 7, 4480-4484, Oct. 2003, Peer-reviwed, We present numerical results of an examination of the current mirror effect in a single-electron turnstile capacitively coupled to a one-dimensional (1D) array of small tunnel junctions. We deal with a 20-junction 1D array and 4-junction turnstile coupled at their center electrodes via a coupling capacitor. A coupling parameter, Q(c), and a current mirror index are introduced to define the strength of coupling and to evaluate the quality of the current mirror effect, respectively. Numerical results show that a finite gate charge of e/2 to the center electrodes of both the 1D array and the turnstile enhances the current mirror effect, where -e is the charge of an electron. To investigate the enhanced current mirror effect, charge propagation in the 1D array under a finite gate charge of e/2 is simulated. It is found that electrons temporarily trapped at the center electrode in the 1D array play an important role in the enhancement of the current mirror effect. (C) 2003 American Institute of Physics.
Scientific journal, English

Intrinsic Josephson junctions in c-axis-oriented La1.85Sr0.15CuO4 thin films
Y Mizugaki; Y Uematsu; SJ Kim; J Chen; K Nakajima; T Yamashita; H Sato; M Naito
JOURNAL OF APPLIED PHYSICS, AMER INST PHYSICS, 94, 4, 2534-2537, Aug. 2003, Peer-reviwed, We investigated current-voltage characteristics (IVCs) of intrinsic Josephson junctions (IJJs) for c-axis oriented La1.85Sr0.15CuO4 thin films. We fabricated IJJs with two kinds of structures. One was a mesa structure with a junction area of 22-194 mum(2) fabricated by using conventional photolithography and Ar-ion milling, and the other was a microbridge structure with a junction area of 1.1-3.6 mum(2) fabricated by using a focused-ion-beam technique. The mesa-type IJJs exhibited resistively-shunted-junction-like IVCs with no hysteresis. The temperature dependence of their critical current followed the Ambegaokar-Baratoff relation. IVCs of the microbridge-type IJJs, on the other hand, exhibited voltage jump and clear hysteresis. The different behaviors between the mesa-type and the microbridge-type IJJs were explained by the different numbers of grain boundaries involved in the IJJs. (C) 2003 American Institute of Physics.
Scientific journal, English

Numerical Investigation for the Shapiro Steps in an RF-Field-Driven SQUID
Y. Mizugaki; K. Sugi; T. Yamashita
Extended Abstracts of the 9th International Supserconductive Electronics Conference, PTh26-1 - PTh26-2, Jul. 2003
International conference proceedings, English

Zero-crossing Shapiro step in a three-junction SQUID magnetically coupled with two phase-shifted RF signals
Y Mizugaki; J Chen; S Nishikata; K Sugi; K Nakajima; T Yamashita
IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 13, 2, 926-929, Jun. 2003, Peer-reviwed, We demonstrate a zero-crossing Shapiro step in a three-junction SQUID (3J-SQUID) coupled with two phase-shifted RF signals. The operation is based on periodical flux quantum transitions in the 3J-SQUID under the zero- and negatively-biasing conditions. A test circuit is fabricated using a Nb/AlOx/Nb junction technology. When we feed RF signals up to 10.5 GHz, we observe a Shapiro step crossing the zero-current axis at the voltage position of the 1st order. The experimental current-voltage characteristics are quantitatively reproduced by simulation. Zero-crossing conditions for the DC offset flux and the RF power are obtained experimentally, which is also confirmed by simulation. A programmable Josephson voltage standard is discussed as one of possible applications.
Scientific journal, English

Analysis of the operation modes of an RF-Field-Driven DC-SQUID
Y Mizugaki; K Sugi
IEICE TRANSACTIONS ON ELECTRONICS, IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG, E86C, 1, 55-58, Jan. 2003, Peer-reviwed, Analysis of the operation modes of an RF-Field-Driven DC-SQUID (RFDS) is presented. We numerically calculate the current-voltage characteristics (IVC) of the RFDS, where the RF signal is coupled to the SQUID loop magnetically. Under no DC offset flux, the IVC exhibit the enhancement of the even-order steps. We first evaluate the dependence of the maximum 2nd step height of the RFDS upon frequency. Contrary to the results for a single junction, the RFDS maintains its step height at a certain value in the low frequency region. The maintained values of the maximum step height are dependent on beta(L). The smaller beta(L) is, the larger the maximum step height becomes. Next, we evaluate the dependence of the current positions of the 2nd step upon the amplitude of the RF signal. Under the low frequency condition, the current positions agree with the interference patterns of the SQUID, which means that the operation of the RFDS is based on the quantum transitions in the SQUID loop. Under the high frequency condition, on the other hand, the current positions agree with the results for the single junction, which means that the quantum transitions does not follow the RIF signal and that the RFDS behaves like a single junction.
Scientific journal, English

Single-electron turnstile locked to charge solitons in a one-dimensional array of small junctions
Y Mizugaki; P Delsing
JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS SHORT NOTES & REVIEW PAPERS, INST PURE APPLIED PHYSICS, 41, 9, 5630-5634, Sep. 2002, Peer-reviwed, We present numerical results on the current mirror effect in a single-electron turnstile capacitively coupled with a one-dimensional (ID) array of small tunnel junctions. Contrary to conventional operation with a sinusoidal signal source, the single-electron turnstile is driven by charge solitons (and anti-solitons) transferred through the ID Arran. Then, the Current through the turnstile can be locked to the current through the ID array; this is the current mirror effect, We numerically demonstrate the current mirror effect in our circuit, where a 4-junction turnstile and a 20-junction 1D array are coupled at their middle nodes via a coupling capacitor. We introduce a coupling parameter, Q(c) to define the strength of Coupling, between the ID array and the turnstile. We also introduce a current mirror index, CMI, to evaluate the quality of the Current mirror effect. The dependence of CMI upon the soliton length, the current through the ID array, and Q(c) is discussed.
Scientific journal, English

Zero-crossing Shapiro Step in a Three-junction SQUID Magnetically Coupled with Two Phase-shifted RF Signals
Y. Mizugaki; J. Chen; S. Nishikata; K. Sugi; K. Nakajima; T. Yamashita
Abstracts of 2002 Applied Superconductivity Conference, 48, Aug. 2002
International conference proceedings, English

Quantum transitions and zero-crossing current steps in a SQUID controlled by multi-phase RF fields
Y Mizugaki; J Chen; K Nakajima; T Yamashita
PHYSICA C-SUPERCONDUCTIVITY AND ITS APPLICATIONS, ELSEVIER SCIENCE BV, 372, 1, 274-277, Aug. 2002, Peer-reviwed, We numerically demonstrate zero-crossing current steps on current-voltage characteristics (IVC) of a three-junction superconducting quantum interference device (SQUID) activated by multi-phase RF magnetic flux. First, we analyze how the quantum state of the SQUID can be controlled by two RF magnetic signals with phase difference of pi/2. It is shown on the quantum diagram that one flux quantum can pass through the SQUID per one cycle of the RF signals without DC biasing current, which results in a zero-crossing step on its IVC. Next, we numerically demonstrate IVC of the SQUID and zero-crossing steps on them. We also investigate the dependence of zero-crossing steps upon the DC offset flux. The results show that the voltage position of zero-crossing steps can be set at one of three values (-Phi(0)f, 0, and Phi(0)f) by tuning the DC offset flux.
(C) 2002 Elsevier Science B.V. All rights reserved.
Scientific journal, English

Single-flux-quantum pump based on a three-junction superconducting quantum interference device
Y Mizugaki; J Chen; S Nishikata; K Sugi; K Nakajima; T Yamashita
APPLIED PHYSICS LETTERS, AMER INST PHYSICS, 80, 24, 4585-4587, Jun. 2002, Peer-reviwed, We demonstrate the operation of a single-flux-quantum (SFQ) pump that is electromagnetically dual to the single-electron pump. The circuit is composed of a three-junction superconducting quantum interference device with three control lines. By applying two phase-shifted rf signals magnetically, the SFQ-pump transfers one SFQ per one cycle of the rf signals even at zero- and negatively-biased condition. The circuit was fabricated using a Nb/AlOx/Nb Josephson junction technology. When we fed rf signals of 4.5 GHz, we observed a Shapiro step crossing the zero-current axis. Periodic dependence of voltage at the zero-biasing state upon dc offset flux was also confirmed. (C) 2002 American Institute of Physics.
Scientific journal, English

Flux-quantum transitions in a three-junction SQUID controlled by two RF signals
Y Mizugaki; J Chen; K Nakajima; T Yamashita
IEICE TRANSACTIONS ON ELECTRONICS, IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG, E85C, 3, 803-808, Mar. 2002, Peer-reviwed, We present analytical and numerical results on the flux-quantum transitions in a three-junction superconducting quantum interference device (3J-SQUID) controlled by two RF signals. The 3J-SQUID has two superconducting loops, and the RF signals are magnetically coupled to the loops. Flux-quantum transitions in the 3J-SQUID loops can be controlled by utilizing the phase difference of the two RF signals. Under proper conditions, we can obtain a situation where one flux quantum passes through the 3J-SQUID per one cycle of the RF signals without DC current biasing, which results in a zero-crossing step on the current-voltage characteristics. In this paper, we first explain the operation principle by using a quantum state diagram of a 3J-SQUID. Next, we numerically simulate RF-induced transitions of the quantum states. A zero-crossing stop on the current-voltage characteristics is demonstrated. We also investigate dependence of zero-crossing steps upon parameters of the 3J-SQUID and RF signals.
Scientific journal, English

Characterization of intrinsic Josephson junctions for La2-xSrxCuO4 single crystals
Y Uematsu; Y Mizugaki; K Nakajima; T Yamashita; S Watauchi; Tanaka, I
PHYSICA C-SUPERCONDUCTIVITY AND ITS APPLICATIONS, ELSEVIER SCIENCE BV, 367, 1-4, 382-387, Feb. 2002, Peer-reviwed, We have fabricated c-axis micro-bridges of La2-xSrxCuO4 (LSCO) single crystals in order to characterize the LSCO intrinsic Josephson junctions (IJJs). The current-voltage characteristics of the micro-bridges exhibited a large hysteresis with a voltage jump of the order 0.5-3 V and no multiple branching structures. A superconducting energy gap was clearly observed on the quasi-particle branch and showed BCS-like temperature dependence. In addition, the temperature dependence of the critical current of the IJJ was in good agreement with the theoretical curves for superconductor-insulator-superconductor (SIS) Josephson junctions. These results demonstrate that the IJJs of LSCO are characterized as stacked series SIS junctions. (C) 2002 Published by Elsevier Science B.V.
Scientific journal, English

Numerical Investigation on the Current Mirror Effect in a Single-Electron Turnstile Coupled with a One-Dimensional Array of Small Tunnel Junctions
Y. Mizugaki; P. Delsing
Proceedings of 2001 International Symposium on Nonlinear Theory and its Applications, 2, 525-528, Nov. 2001, Peer-reviwed
International conference proceedings, English

Single-electron signal modulator designed for a flash analog-to-digital converter
Y Mizugaki; P Delsing
JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS SHORT NOTES & REVIEW PAPERS, INST PURE APPLIED PHYSICS, 40, 10, 6157-6162, Oct. 2001, Peer-reviwed, We demonstrate a 4-bit flash analog-to-digital converter (FADC) composed of a single-electron signal modulator (SESM) with a capacitive voltage divider (CVD). In the CVD, we utilize the self-capacitance of floating metal islands, and hence, maximum input impedance can be realized with the CVD. We also analyze the characteristics of the CVD with stray capacitance. The signals from the CVD are detected by four single-electron transistors (SETs), and their outputs, processed at quantizers, represent gray-coded digital signals. We designed two kinds of layouts for the CVDs, and fabricated two samples for each layout by photolithography, electron-beam lithography, and the shadow evaporation of aluminum. Measurements were executed at approximately 30 mK. Four-bit FADC operation was successfully simulated using experimental results. We also discuss the possibility of higher resolution with our circuit configuration.
Scientific journal, English

Subgap structures in the current-voltage properties of La2-xSrxCuO4 intrinsic Josephson junctions
Y Uematsu; N Sasaki; Y Mizugaki; K Nakajima; T Yamashita; S Watauchi; Tanaka, I
PHYSICA C, ELSEVIER SCIENCE BV, 362, 1-4, 290-295, Sep. 2001, Peer-reviwed, We investigated current-voltage (I-V) properties of intrinsic Josephson junctions in c-axis micro-bridges (similar to 20 mum(2) area for ab plane and similar to1 mum length along the c-axis) of La2-xSrxCuO4 single crystals. The micro-bridges were fabricated by the focused-ion-beam etching technique. We found periodic conductance peaks below the gap voltage in the RCSJ-like I-V curves of the intrinsic Josephson junctions. We discuss possible explanations and show that the subgap structures can be explained by coupling between ac Josephson oscillation and Josephson plasma oscillation in La2-xSrxCuO4. (C) 2001 Elsevier Science B.V. All rights reserved.
Scientific journal, English

Josephson plasma in Bi2Sr2CaCu2O8+delta detected by Nb/AlOx/Nb junction
Y Yamada; Y Uematsu; Y Mizugaki; K Nakajima; T Yamashita
PHYSICA C, ELSEVIER SCIENCE BV, 362, 1-4, 244-246, Sep. 2001, Peer-reviwed, We fabricated Nb/AlOx/Nb Josephson junctions on Bi2Sr2CaCu2O8+delta (BSCCO) single crystals to detect the Josephson plasma in BSCCO. A thin gold layer was, employed between BSCCO and Nb/AlOx/Nb to avoid interdiffusion of oxygen in BSCCO. We measured the current-voltage properties of the Nb/AlOx/Nb junctions in a liquid helium bath, and observed clear periodic step structures. A characteristic frequency corresponding to the voltage spacing of the steps was 63 GHz, which agreed with the Josephson plasma frequency of BSCCO. The result indicates that the Josephson plasma in BSCCO can interact with the ac Josephson current of the closely coupled Nb/AlQ(x)/Nb Josephson junctions. (C) 2001 Elsevier Science B.V. All rights reserved.
Scientific journal, English

Quantum transitions and zero-cross current-steps in a SQUID controlled by multi-phase RF fields
Y. Mizugaki; J. Chen; K. Nakajima; T. Yamashita
Abstracts of 5th European Conference on Applied Superconductivity, 145, Aug. 2001
International conference proceedings, English

Characterization of intrinsic Josephson junctions for La_2-x_Sr_x_CuO_4_ single crystals
Y. Uematsu; Y. Mizugaki; K. Nakajima; T. Yamashita; S. Watauchi; I. Tanaka
Abstracts of International symposium on Superconducting Device Physics, P-E01, Jun. 2001
International conference proceedings, English

Detection of Josephson Plasma in High-Tc Superconductors with low-Tc Josephson Junctions
Y. Yamada; Y. Mizugaki; K. Nakajima; T. Yamashita
Extended Abstracts of the 8th International Superconductive Electronics Conference (ISEC'01), 439-440, Jun. 2001
International conference proceedings, English

Fabrications of intrinsic Josephson junctions using (001) oriented LSCO thin films
Y. Uematsu; S. Kim; Y. Mizugaki; J. Chen; K. Nakajima; T. Yamashita; H. Sato; M. Naito
Extended Abstracts of the 8th International Superconductive Electronics Conference (ISEC'01), 407-408, Jun. 2001
International conference proceedings, English

Flux-quantum transitions in a three-junction SQUID controlled by two RF signals
Y. Mizugaki; J. Chen; K. Nakajima; T. Yamashita
Extended Abstracts of the 8th International Superconductive Electronics Conference (ISEC'01), 289-290, Jun. 2001
International conference proceedings, English

Microwave induced steps in RF-Field-driven DC SQUID and its potential applications
T Kondo; Y Mizugaki; J Chen; K Nakajima; T Yamashita
IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 11, 1, 900-903, Mar. 2001, Peer-reviwed, We have been studying an RF-Field-driven DC SQUID (RFDS) that exhibits RF-induced-current-steps larger than those of single junctions at lower normalized frequency and a strong selection rule for the step orders which depends on the external DC magnetic field. In RFDS, even order steps are dominant in the absence of DC magnetic field. Contrarily, a DC magnetic field of a half flux quantum dominantly enhances odd order steps. Therefore the output of an RFDS can be switched between two voltage levels corresponding to the RF-induced-step by an external DC field input for a certain bias condition. We carried out numerical simulations to characterize the switching properties of the RFDS for various bias conditions, including RF circulating currents end DC bias current.
Scientific journal, English

Switching device based on RF-field-driven high-T-C SQUID
T Kondo; Y Mizugaki; K Saito; K Nakajima; T Yamashita
IEICE TRANSACTIONS ON ELECTRONICS, IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG, E84C, 1, 55-60, Jan. 2001, Peer-reviwed, A voltage mode logic device based on RF-Field-driven DC-SQUID (RFDS) using high-T-C superconducting Josephson junctions has been proposed. RFDS produces large RF-induced steps, and the orders of steps are strongly selected DC magnetic flux crossing the SQUID loop superposing with RF magnetic field. In this paper. we present the experimental results of RFDS fabricated bq using YBCO grain boundary Josephson junctions. The results are evaluated with numerical simulations. The enhancement of RF-induced steps, the strong selection of step orders and the switching performance are demonstrated.
Scientific journal, English

Investigation of microwave responses in BSCCO-2212 intrinsic Josephson junctions up to short millimeter wavebands
HB Wang; J Chen; Y Aruga; T Tachiki; Y Mizugaki; K Nakajima; T Yamashita; PH Wu
PHYSICA C, ELSEVIER SCIENCE BV, 341, 2737-2738, Nov. 2000, Peer-reviwed, With an overlap structure for improving coupling, intrinsic Josephson junctions (IJJs) with an a-b plane area down to 1 mum(2) were fabricated on argon-annealed Bi2Sr2CaCu2O8+x single crystals. Responses at frequencies from a few to 200 gigahertz were carefully investigated by measuring the samples' current-voltage (I-V) curves. The experimental results indicate that high frequency applications of IJJs over a very wide frequency range are potentially possible.
Scientific journal, English

Microwave induced steps in RF-Field-Driven dc SQUID and its potential applications
T. Kondo; Y. Mizugaki; K. Saito; J. Chen; K. Nakajima; T. Yamashita
Technical Program Book With Abstracts of 2000 Applied Superconductivity Conference, 97, Sep. 2000
International conference proceedings, English

Detection of Josephson Plasma in Bi_2_Sr_2_CaCu_2_O_x_ using Nb/Al-AlO_x_/Nb Josephson Junction
Y. Yamada; Y. Uematsu; Y. Mizugaki; K. Nakajima; T. Yamashita
Abstracts of 2nd International Symposium on Intrinsic Josephson Effects and Plasma Oscillations in High-Tc Superconductors, 28, Aug. 2000
International conference proceedings, English

Subgap structures in the current - voltage properties of La_2-x_Sr_x_CuO_4_ intrinsic Josephson junctions
Y. Uematsu; N. Sasaki; Y. Mizugaki; K. Nakajima; T. Yamashita; S. Watauchi; I. Tanaka
Abstracts of 2nd International Symposium on Intrinsic Josephson Effects and Plasma Oscillations in High-Tc Superconductors, 34, Aug. 2000
International conference proceedings, English

Responses of BSCCO-2211 intrinsic Josephson junctions to microwave irradiation at short millimeter waveband
H. B. Wang; Y. Aruga; T. Tachiki; Y. Mizugaki; J. Chen; K. Nakajima; T. Yamashita; P. H. Wu
Abstracts of 6th Inernational Conference Materials and Mechanisms of Superconductivity and Hight Temperature Superconductors, 491, Feb. 2000
International conference proceedings, English

Two-junction SQUID controlled by both DC and RF magnetic flux
Y Mizugaki; K Saito; T Kondo; J Chen; K Nakajima; AI Braginski; T Yamashita
ADVANCES IN SUPERCONDUCTIVITY XII, SPRINGER-VERLAG TOKYO, 1114-1116, 2000, Peer-reviwed, The behavior of Shapiro steps is numerically investigated for a two-junction (DC) SQUID under the both DC and RF (microwave) field. In contrast to a single Josephson junction, such SQUID can exhibit strong Shapiro steps over a wide frequency range, even when the normalized frequency is much smaller than unity We can control the order of generated steps by adjusting the DC offset field and thus obtain an enhancement of their height. We also propose some applications of such effects to microwave detectors and switching devices.
International conference proceedings, English

Microwave responses of BSCCO-2212 intrinsic Josephson junctions at frequencies up to 100 GHz
HB Wang; T Tachiki; Y Aruga; Y Mizugaki; J Chen; K Nakajima; T Yamashita; PH Wu
ADVANCES IN SUPERCONDUCTIVITY XII, SPRINGER-VERLAG TOKYO, 1108-1110, 2000, Peer-reviwed, C-axis junction-stacks, with a-b plane sizes of 10 microns by 10 microns, were patterned on Bi2Sr2CaCu2O8 Single crystals. We measured the current-voltage (I-V) characteristics with irradiation at a few to 100 gigahertz. At a few gigahertz and very high power level, current steps were stimulated and the voltage separations between them were independent of the microwave power. Under irradiation at 100 GHz, in addition to the suppression of critical currents, we successfully performed harmonic mixings between the 100 GHz signal and up to the 100(th) harmonic of a local oscillator at about 1 GHz. These experimental results show that intrinsic Josephson junctions can be good candidates for high frequency applications, and harmonic mixing may be a useful probe to investigate plasma phenomena in layered superconductors.
International conference proceedings, English

Josephson switching device utilizing the quantum transitions in a superconducting quantum interference device loop
Y Mizugaki; K Saito; AI Braginski; T Yamashita
JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS SHORT NOTES & REVIEW PAPERS, JAPAN J APPLIED PHYSICS, 39, 1, 55-60, Jan. 2000, Peer-reviwed, We propose a new type of Josephson switching device which utilizes quantum transitions in a superconducting quantum interference device (SQUID) loop. This device is driven by a DC bias current and RF magnetic field. The output voltage is determined by the transition rate and the AC-Josephson relationship. We investigate the desirable device parameters by simulation. Two parameters, the maximum step height and the overlapped current region for the 0th and 1st steps, are plotted as functions of frequency and power of the RF-field activation. We also derive the relationship between the gain and device parameters, The analytical relationship is in good agreement with the numerical results. Besides the simple switching operation, a flip-flop operation is also successfully simulated. The results indicate that the device with appropriate parameters is suitable for switching applications.
Scientific journal, English

Magnetically enhanced terahertz response of Josephson junctions
Y Mizugaki; J Chen; K Nakajima; T Yamashita
IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 9, 4, 4677-4681, Dec. 1999, Peer-reviwed, We investigate the magnetic field effects on the terahertz (THz) response of grain boundary Josephson junctions. First, we show some experimental results of the THz response enhanced by a de magnetic field. The experimental results and device configuration indicate that the THz RF magnetic field plays a role in enhancing the response. Second, we numerically simulate the current-voltage characteristics and obtain the power dependence of Shapiro steps. Since the junctions are wide compared to the inferred Josephson penetration depth, multiple current paths within a junction are possible and superconducting quantum interference device (SQUID) models should be used. Two kinds of SQUID models are used: an RF-current drive model and an RF-field activation model. Shapiro step enhancement by a de magnetic field can be reproduced with the use of the RP-field activation model. Finally, we discuss step-height dependence on SQUID parameters as well as give a qualitative explanation for the different predictions of two SQUID models.
Scientific journal, English

Flux-flow resonant current steps in intrinsic Josephson junctions on Bi2Sr2CaCu2O8 single crystal
HB Wang; T Tachiki; Y Aruga; Y Mizugaki; J Chen; K Nakajima; T Yamashita; PH Wu
SUPERCONDUCTOR SCIENCE & TECHNOLOGY, IOP PUBLISHING LTD, 12, 11, 1004-1006, Nov. 1999, Peer-reviwed, A mesa with a-b plane dimensions of 12 mu m x 12 mu m was patterned on Bi2Sr2CaCu2O8 Single crystal, after which two separate electrical contacts were carefully fabricated on the top of the mesa to ensure a standard four-probe arrangement. With contact resistance excluded, the measured current-voltage (I-V) curves featured high voltage resolution. Voltage jumps up to 20 mV and remarkable hysteresis at 4.2 K indicated typical superconductor-insulator-superconductor properties. A few sharp current steps started to manifest themselves clearly when a magnetic field of about 10 kOe was applied parallel to the a-b plane. Carefully studied were the dependences of the current steps on the magnetic fields and the operating temperatures. We attributed the field-induced steps to the flux-flow resonances, and the multisteps implied different modes existing in the stacked intrinsic junctions. The voltage region at which the steps occurred was of the order of millivolts, indicating possible high-frequency applications at mm and sub-mm wavebands.
Scientific journal, English

RF responses of double-junction SQUID models
Y Mizugaki; J Chen; K Nakajima; T Yamashita
SUPERCONDUCTOR SCIENCE & TECHNOLOGY, IOP PUBLISHING LTD, 12, 11, 992-994, Nov. 1999, Peer-reviwed, We present numerical investigation of the RF properties of a double-junction SQUID model, which is referred to as an RF-field-driven double-junction SQUID (RFDS). The RFDS generates large current steps, the order of which can be controlled by external de field. We simulate the current-voltage characteristics of the RFDS in the normalized frequency range from 0.065 to 5.0. In comparison with the results for a single junction, the step heights of the RFDS are much larger for the low frequency region; e.g. the first step of the REDS becomes nine times larger than that of a single junction when a de flux of 0.5 phi(0) is applied (phi(0) is a flux quantum). For the high frequency region, the step height of the RFDS is comparable to that of a single junction. The results suggest that the REDS should be applicable as a wide-band RF detector.
Scientific journal, English

Harmonic frequency mixing in Bi2Sr2CaCu2O8+X intrinsic Josephson junctions
HB Wang; Y Aruga; T Tachiki; Y Mizugaki; J Chen; K Nakajima; T Yamashita; PH Wu
APPLIED PHYSICS LETTERS, AMER INST PHYSICS, 75, 15, 2310-2312, Oct. 1999, Peer-reviwed, In a c-axis junction stack (10 mu mx10 mu m in a-b plane) patterned on a Bi2Sr2CaCu2O8+X single crystal, we performed harmonic mixings between a 100 GHz signal and up to the 98th harmonic of a local oscillator at about 1 GHz. The dependence of P-IF on V, where P-IF is the mixing output at the intermediate frequency and V is the dc voltage across the junction stack, was strongly affected by the local oscillator power levels. For low values of local oscillator power, the optimum operation point where P-IF became maximum was around zero bias, and typical multi-branch structure of P-IF vs V curves were observed. For high values of local oscillator power, the optimum operation point moved to the high-voltage region. In both cases, interesting oscillations occurred on the P-IF vs V curves. Our experimental results led us to believe that intrinsic Josephson junctions can be good candidates for high frequency applications and the harmonic mixing may be a useful probe to investigate plasma phenomena in the layered superconductors. (C) 1999 American Institute of Physics. [S0003-6951(99)05341-3].
Scientific journal, English

Magnetic isolation on a superconducting ground plane
Y Mizugaki; K Yanagisawa; T Onomi; T Yamashita; K Nakajima; H Yamamori; A Shoji
JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS SHORT NOTES & REVIEW PAPERS, INST PURE APPLIED PHYSICS, 38, 10, 5869-5870, Oct. 1999, Peer-reviwed, We investigate the magnetic isolation on a superconducting ground plane (GP) by measuring the mutual inductance between two lines. We evaluate the shielding effect of three structures: a simple flat GP, a GP with a shielding wall, and a GP with a covering layer. The third structure reduces the mutual inductance as much as -13 dB compared with the first one. We also derive an expression of the mutual inductance for the first structure.
Scientific journal, English

YBCOSQUIDs fabricated by field-emission electron beam source
SJ Kim; J Chen; Y Mizugaki; K Nakajima; T Yamashita
IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 9, 2, 3089-3092, Jun. 1999, Peer-reviwed, We report the applicability of YBa2Cu3O7-y., (YBCO) SQUIDs fabricated by field-emission electron beam source. The junctions show hysteresis and self-resonance steps related to a high frequency resonance in the de SQUID loop at a voltage V-res = Phi(0) / 2 pi(LC / 2)(1/2) around 0.3 T-c, The noise spectrum of the SQUIDs was measured with de-bias schemes at different temperatures and showed values around 10(-4)Phi(0)/Hz(1/2) down to frequencies of 10 Hz at 40 K. The influence of magnetic flux, operating temperatures and flux-voltage transfer factor( \ dV/d Phi \) were investigated, We also tested inverter operation of a de-biased Josephson logic gate composed of an rf SQUID and a de SQUID to realize logic circuit performance. Operation of the inverter has been successfully demonstrated although the operating temperature is low, around 10 K.
Scientific journal, English

Microwave-induced current steps in intrinsic Josephson junctions patterned on Bi2Sr2CaCu2O8 single crystal
HB Wang; Y Aruga; T Tachiki; Y Mizugaki; J Chen; K Nakajima; T Yamashita; PH Wu
APPLIED PHYSICS LETTERS, AMER INST PHYSICS, 74, 24, 3693-3695, Jun. 1999, Peer-reviwed, With a 10 mu mx10 mu m mesa patterned on Bi2Sr2CaCu2O8 single crystals, we measure the current-voltage (I-V) curves of a stack of intrinsic Josephson junctions. Current steps are observed at an equal voltage spacing of 4 mV when the sample is subjected to microwave radiation at around 7 GHz. With increase of the microwave power, more steps occur while the spacing between neighboring steps does not seem to change. The magnitude of each step depends on the microwave power in an oscillating way. Tuning the microwave frequency causes such steps to occur over separate frequency ranges, and each range is quite narrow. A temperature rise from 4.2 to 14.3 K completely quenches the step structures. Possible explanations for the step structures, based on resonances excited by microwave or geometric resonances in the junction cavity, are discussed. (c) 1999 American Institute of Physics. [S0003-6951(99)04024-3].
Scientific journal, English

Flux-flow resonant current steps in intrinsic Josephson junctions on Bi_2_Sr_2_CaCu_2_O_8_ single crystal
H. B. Wang; T. Tachiki; Y. Aruga; Y. Mizugaki; J. Chen; K. Nakajima; T. Yamashita; P. H. Wu
Extended Abstracts of 7th International Superconductive Electronics Conference, 476-478, Jun. 1999
International conference proceedings, English

RF responses of double-junction SQUID models
Y. Mizugaki; J. Chen; K. Nakajima; T. Yamashita
Extended Abstracts of 7th International Superconductive Electronics Conference, 460-462, Jun. 1999
International conference proceedings, English

Intrinsic Josephson junctions in oxygen-deficient YBa2Cu3O7-delta film deposited on a substrate step
HB Wang; J Chen; T Tachiki; Y Mizugaki; K Nakajima; T Yamashita
JOURNAL OF APPLIED PHYSICS, AMER INST PHYSICS, 85, 7, 3740-3744, Apr. 1999, Peer-reviwed, Using c-axis-oriented oxygen-deficient YBa2Cu3O7-delta film deposited across a low-angle step on a SrTiO3 substrate, we successfully demonstrated intrinsic Josephson effects. In addition to several voltage jumps of large amplitudes (a few millivolts) and remarkable hysteresis on the dc current-voltage curves, we observed upturns on the current-voltage curves under microwave irradiation which appeared at increasingly high voltages with increasing microwave power. We proposed to explain this observation in terms of high-order microwave-induced Shapiro steps. (C) 1999 American Institute of Physics. [S0021-8979(99)00407-7].
Scientific journal, English

Fluxoid-type logic circuits
K Nakajima; Y Mizugaki; T Onomi; T Yamashita
PHYSICS AND APPLICATIONS OF MESOSCOPIC JOSEPHSON JUNCTIONS, PHYSICAL SOCIETY JAPAN, 267-288, 1999, Peer-reviwed, Several families of fluxoid-type logic circuits have been demonstrated. We have proposed an ICF (INHIBIT Controlled by Fluxon) gate as the basic circuit of the phase-mode logic family, and fabricated the adder circuit. The experimental result demonstrates the normal adder operation predicting one carry operation within 20psec. The performance of Josephson devices is improved by use of the junctions with high current density J(c). We may use the high J(c) junctions without external resistive shunt in fluxoid-type logic circuits because of the reduction of the junction hysteresis. And one of the way to overcome the large area occupancy for geometric inductance is to utilize the kinetic inductance of a Josephson junction itself. We discuss various aspects which are brought about to exchange the geometric inductor for the high J(c) inductor junction.
International conference proceedings, English

YBCO SQUIDs fabricated by field-emission electron beam source
S. J. Kim; J. Chen; Y. Mizugaki; K. Nakajima; T. Yamashita
IEEE Transactions on Applied Superconductivity, 9, 2, 3089-3092, 1999, We report the applicability of YBa 2Cu 3O 7-y (YBCO) SQUIDs fabricated by field-emission electron beam source. The junctions show hysteresis and self-resonance steps related to a high frequency resonance in the dc SQUID loop at a voltage V res = φ 2 / 2π(LC / 2) 1/2 around 0.3 T c. The noise spectrum of the SQUIDs was measured with de-bias schemes at different temperatures and showed values around 10 -4 φ 0/Hz 1/2 down to frequencies of 10 Hz at 40 K. The influence of magnetic flux, operating temperatures and flux-voltage transfer factor (|dV/d<
SJ ) were investigated. We also tested inverter operation of a de-biased Josephson logic gate composed of an rf SQUID and a dc SQUID to realize logic circuit performance. Operation of the inverter has been successfully demonstrated although the operating temperature is low, around 10 K. © 1999 IEEE.
Scientific journal, English

Switching delay of a nonlatching Josephson gate evaluated from ring oscillator operation
Y Mizugaki; K Nakajima; A Shoji
IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 8, 4, 188-191, Dec. 1998, Peer-reviwed, The authors present the experimental results for the switching delay of a de-biased nonlatching Josephson gate (a coupled-superconducting quantum interference device gate), The measurement is executed by the use of a ring oscillator (RO) method, A frequency-to-voltage converter is used to evaluate the oscillation frequency of the RO, The circuit is designed and fabricated using a 2.5-kA/cm(2) Nb/AlOx/Nb Josephson junction technology, The results show the minimum switching delay of 18 ps.
Scientific journal, English

Numerical evaluation for the high-frequency response of Josephson junctions having finite capacitance
Y Mizugaki; JA Chen; K Nakajima; T Yamashita
JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS SHORT NOTES & REVIEW PAPERS, JAPAN J APPLIED PHYSICS, 37, 11, 5971-5972, Nov. 1998, Peer-reviwed, The high-frequency response of a Josephson junction is numerically investigated. The resistively shunted junction (RSJ) model and the resistively and capacitively shunted junction (RCSJ) model are employed. Simulation results for the Shapiro steps are different between the two models. The difference with respect to the RF current is explained by employing a simple resistor and capacitor model.
Scientific journal, English

Phase-mode circuits for high-performance logic
T Onomi; Y Mizugaki; H Satoh; T Yamashita; K Nakajima
IEICE TRANSACTIONS ON ELECTRONICS, IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG, E81C, 10, 1608-1617, Oct. 1998, Peer-reviwed, We present two types of ICF (INHIBIT Controlled by Fluxon) gates as the basic circuits of the phase-mode logic family, and fabricate an adder circuit. The experimental result demonstrates that the carry operation followed up to 99 GHz input pulses. The performance of Josephson devices is improved by the use of junctions with high current density (J(c)). We may use the high-J(c) junctions without external resistive shunt in the phase-mode logic circuits because of reduction of the junction hysteresis. One of the ways to overcome the large area occupancy For geometric inductance is to utilize the effective inductance of a Josephson junction itself. We investigate a circuit construction with high-J(c) inductor junctions, intrinsically overdumped junctions and junction-type resistors for the compactness of circuit integration, and discuss various aspects of the circuit construction.
Scientific journal, English

Implementation of phase-mode logic circuits based on new integration design
T. Onomi; Y. Mizugaki; K. Nakajima; T. Yamashita
Technical Program Book With Abstracts of 1998 Applied Superconductivity Conference, 89, Sep. 1998
International conference proceedings, English

Neuron-Based A/D Converter Integrated with Josephson Devices
Y. Mizugaki; K. Nakajima
Proc. 1998 Int. Symp. Nonlinear Theory and Its Applications, 2, 441-444, Sep. 1998, Peer-reviwed
International conference proceedings, English

Numerical simulation for digital applications of a coupled-SQUID gate with d.c.-biasing
Yoshinao Mizugaki; Koji Nakajima
Applied Superconductivity, Elsevier {BV}, 6, 7-9, 405-408, Jul. 1998, Peer-reviwed
Scientific journal, English

Static characteristics of superconducting quantum interference devices utilizing the equivalent inductance of Josephson junctions
Y Mizugaki; K Nakajima
ELECTRONICS AND COMMUNICATIONS IN JAPAN PART II-ELECTRONICS, SCRIPTA TECHNICA-JOHN WILEY & SONS, 81, 6, 1-7, Jun. 1998, It is necessary to miniaturize inductors for large-scale integration of Josephson devices. Utilizing the equivalent inductance of Josephson junctions is one promising method to realize small inductors. In this paper we calculate the static characteristics of some superconducting quantum interference devices (SQUIDs) utilizing the equivalent inductance, and we compare the results with those of SQUIDs employing the normal inductors. We also discuss the current distribution before and after the transition of the gate junctions. (C) 1998 Scripta Technica, Electron Comm Jpn Pt 2, 81(6): 1-7, 1998.
Scientific journal, English

A new analog content addressable memory for building a new intelligent system and VLSI implementation
T. Harada; Y. Mizugaki; K. Nakajima
Proc. the 2nd R.I.E.C. Int. Symp. Design and Architecture of Information Processing Systems Based on The Brain Information Principles (DAIPS), 283-286, Mar. 1998, Peer-reviwed
International conference proceedings, English

Static Characteristics of Superconducting Quantum Interference Devices Utilizing the Equivalent Inductance of Josephson Junctions
水柿義直; 中島康治
The Transactions of the Institute of Electronics, Information and Communication Engineers, The Institute of Electronics, Information and Communication Engineers, Vol. J81-C-II, 2, 259-265, Feb. 1998, Peer-reviwed, ジョセフソンデバイスの小型化を実現するためには, デバイスの基本構成要素の一つであるインダクタの小型化が不可欠である.これまでにインダクタの小型化の手法として, ジョセフソン接合の等価インダクタンスの利用が提案されている.本研究では, ジョセフソン接合の等価インダクタンスを利用した超伝導量子干渉素子の静特性を求め, 通常のインダクタにより構成される超伝導量子干渉素子の特性と比較する.またゲート用の接合が電圧状態に遷移した後の電流分布の変化がインダクタンス用の接合に及ぼす影響についても考察する.
Scientific journal, Japanese

A new analog content addressable memory for building a new intelligent system and VLSI implementation
T. Harada; Y. Mizugaki; K. Nakajima
Proc. 1997 Int. Symp. Nonlinear Theory and Its Applications, 2, 869-872, Nov. 1997, Peer-reviwed
International conference proceedings, English

Design and fabrication of an adder circuit in the extended phase-mode logic
T Onomi; T Yamashita; Y Mizugaki; K Nakajima
IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 7, 2, 3172-3175, Jun. 1997, Peer-reviwed, We present the design and the fabrication of an adder circuit in the extended phase-mode logic Family. The phase-mode logic is a single Aux quantum(SFQ) logic which utilizes an SFQ as an information bit carrier. The single-bit adder circuit is made up of an INHIBIT gate which is the basic device of the phase-mode logic, The circuit has been designed and fabricated using Nb/AlOx/Nb Josephson junctions with Josephson critical current density of 1.0kA/cm(2). In order to confirm the circuit operation, the fabricated adder circuit has been tested at low speed. Far investigating the possibility of a high-frequency operation, dc voltages generated by fluxon pulse trains have been measured. From the Josephson voltage-frequency relation, the result shows that the circuit has potential to complete the carry operation within 20psec.
Scientific journal, English

Characterization of the fluxoid Josephson transmission line and the application to phase-mode circuits
T. Onomi; Y. Mizugaki; K. Nakajima; T. Yamashita
Extended Abstracts of 6th International Superconductive Electronics Conference, 3, 296-298, Jun. 1997
International conference proceedings, English

Numerical Simulation for Digital Applications of a Coupled-SQUID Gate with DC-Biasing
Y. Mizugaki; K. Nakajima
Extended Abstracts of 6th International Superconductive Electronics Conference, 2, 272-274, Jun. 1997
International conference proceedings, English

Phase Mode Logic and High Jc Junctions
K. Nakajima; Y. Mizugaki; T. Onomi; T. Yamashita
Extended Abstracts of The 5th International Workshop on High-Temperature Superconducting Electron Devices, 49-50, May 1997
International conference proceedings, English

Numerical investigation and model approximation for the hysteretic current-voltage characteristics of Josephson junctions with nonlinear quasiparticle resistance
Y Mizugaki; K Nakajima
JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS SHORT NOTES & REVIEW PAPERS, JAPAN J APPLIED PHYSICS, 36, 1A, 110-113, Jan. 1997, Peer-reviwed, We present a model analysis for the current-voltage (I-V) characteristics of Josephson junctions having superconductor-insulator-superconductor (SIS) structure. The numerical result for the V-m value, which is the product of the maximum supercurrent and the observed subgap resistance, shows a marked decrease with increasing junction critical current density (J(c)). The marked decrease is independent of leak current. Increasing J(c) reduces the junction capacitance C-J and enlarges the amplitude of the junction voltage oscillation. Nonlinearity of the quasiparticle resistance restricts the voltage oscillation amplitude to the gap voltage, which results in the rapid decrease of the V-m value. In this paper, we introduce a sinusoidal oscillation model for the junction voltage, and derive the approximated expressions for the V-m value. The model approximation results agree well with the numerical results.
Scientific journal, English

Binary counter with new interface circuits in the extended phase-mode logic family
T Onomi; Y Mizugaki; T Yamashita; K Nakajima
IEICE TRANSACTIONS ON ELECTRONICS, IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG, E79C, 9, 1200-1205, Sep. 1996, Peer-reviwed, A binary counter circuit in the extended phase-mode logic (EPL) family is presented. The EPL family utilizes a single flux quantum as an information bit carrier. Numerical simulations shaw that a binary counter circuit with a Josephson critical current density of I kA/cm(2) can operate up to a 30 GHz input signal. The circuit has been fabricated using Nb/AlOx/Nb Josephson junction technology. New interface circuits are employed in the fabricated chip. A low speed test result shows the correct operation of the binary counter.
Scientific journal, English

Design and Fabrication of an Adder Circuit in the Extended Phase-Mode Logic
T. Onomi; Y. Mizugaki; T. Yamashita; K. Nakajima
Technical Program Book With Abstracts of 1996 Applied Superconductivity Conference, 149, Aug. 1996
International conference proceedings, English

Experimental operation of an RS flip-flop composed of nonlatching Josephson gates
Y Mizugaki; T Onomi; K Nakajima; T Yamashita
IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 6, 2, 90-93, Jun. 1996, Peer-reviwed, We present the experimental implementation of an RS flip-flop (RS-FF) composed of de-biased coupled-SQUID (C-SQUID) gates, The C-SQUID gate is a combination of a single-junction SQUID and a double-junction SQUID. This gate utilizes nonhysteretic Josephson junctions and it is operated in nonlatching mode with de-biasing, Several logical functions are able to be realized with a C-SQUID gate by adjusting the input bias and the input signal levels, The speed performance of the gate is evaluated by simulation for ring oscillators, and the minimum switching delay of 6.5 ps/stage is obtained under Josephson critical current density of 10 kA/cm(2). We have fabricated the RS-FF composed of two C-SQUID NOR gates, The circuit is integrated using a Nb/AlOx/Nb junction technology and its operation is demonstrated experimentally.
Scientific journal, English

Superconducting Phase-Mode Logic Circuit Using a Resistive Ground Contact
T. Onomi; Y. Mizugaki; K. Nakajima; T. Yamashita
Abstracts of International Workshop on Quantum Mechanical Computer, L7, Dec. 1995
International conference proceedings, English

EXTENDED PHASE-MODE LOGIC-CIRCUITS WITH RESISTIVE GROUND CONTACT
T ONOMI; Y MIZUGAKI; K NAKAJIMA; T YAMASHITA
IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 5, 3, 3464-3471, Sep. 1995, Peer-reviwed, We present an extended phase-mode logic (EPL) circuits which have resistive ground contact. The phase-mode logic utilizes magnetic flux-transfer and is based on pulse propagation, i.e., it is one of single flux quantum systems. The proposed logic circuits of the EPL family can have the same ground reference, contrary to the original phase-mode circuits. Therefore, it is possible to couple different EPL elements on a single ground reference. Basic components of the EPL family (a phase-conserving branch, a phase-distributing branch, and an INHIBIT gate controlled by fluxon) are presented. The phase-distributing branch and the INHIBIT gate have been fabricated using a Nb/AlOx/Nb Josephson-junction technology and tested. A fan-in operation of the phase-distributing branch and the first full operation of the INHIBIT gate are successfully demonstrated. As an example of the EPL logic circuits consisting of plural gates on a single ground reference, a simulation of a 2-bit full adder circuit is also presented.
Scientific journal, English

Experimental Realization of Extended Phase-Mode Logic Elements
T. Onomi; Y. Mizugaki; K. Nakajima; T. Yamshita
Extended Abstracts of Fifth International Superconductive Electronics Conference, 195-197, Sep. 1995
International conference proceedings, English

DC-Biased Flip-Flop Composed of Coupled-SQUID Gates
Y. Mizugaki; K. Nakajima; T. Yamashita
Extended Abstracts of Fifth International Superconductive Electronics Conference, 34-36, Sep. 1995
International conference proceedings, English

SUPERCONDUCTING NEURAL CIRCUITS USING SQUIDS
Y MIZUGAKI; K NAKAJIMA; Y SAWADA; T YAMASHITA
IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 5, 2, 3168-3171, Jun. 1995, Peer-reviwed, Superconducting implementation of neural circuits is presented. A neuron element is composed of a coupled-SQUID, which is a combination of a single-junction SQUID and a double-junction SQUID. A synapse element is composed of multiple double-junction SQUIDs. To demonstrate the abilities of these circuits experimentally, a 3-bit neural-based A/D converter, which contains three neurons and three synapses, has been fabricated using a niobium integration technology. This is the first successful implementation of both neuron and active synapse elements into a superconducting neural network.
Scientific journal, English

NEURO-BASE JOSEPHSON FLIP-FLOP
Y MIZUGAKI; K NAKAJIMA; T YAMASHITA
IEICE TRANSACTIONS ON ELECTRONICS, IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG, E78C, 5, 531-534, May 1995, Peer-reviwed, We present a superconducting neural network which functions as an RS flip-flop. We employ a coupled-SQUID as a neuron, which is a combination of a single-junction SQUID and a double-junction SQUID. A resistor is used as a fixed synapse. The network consists of two neurons and two synapses. The operation of the network is simulated under the junction current density of 100 kA/cm(2). The result shows that the network is operated as an RS flip-flop with clock speed capability up to 50 GHz.
Scientific journal, English

Superconducting Neural Circuits Using SQUIDs
Yoshinao Mizugaki; Koji Nakajima; Yasuji Sawada; Tsutomu Yamashita
IEEE Transactions on Applied Superconductivity, 5, 2, 3168-3171, 1995, Superconducting implementation of neural circuits is presented. A neuron element is composed of a coupled-SQUID, which is a combination of a single-junction SQUID and a double-junction SQUID. A synapse element is composed of multiple double-junction SQUIDs. To demonstrate the abilities of these circuits experimentally, a 3-bit neural-based A/D converter, which contains three neurons and three synapses, has been fabricated using a niobium integration technology. This is the first successful implementation of both neuron and active synapse elements into a superconducting neural network. © 1995 IEEE
Scientific journal, English

Flip-flop circuits using dc-biased coupled-SQUID gates
Y Mizugaki; K Nakajima; T Yamashita
APPLIED SUPERCONDUCTIVITY 1995, VOLS. 1 AND 2, IOP PUBLISHING LTD, 148, 1713-1716, 1995, Peer-reviwed, We present a de-biased Josephson logic gate and its application to an RS Flip-Flop (RS-FF). The logic gate is composed of a single-junction SQUID and a double-junction SQUID, which we call a coupled-SQUID (C-SQUID). The C-SQUID gate utilizes non-hysteretic Josephson junctions and is operated in non-latching mode with de-biasing. The RS-FF is composed of two C-SQUID NOR gates. The performance of the single gate and the RS-FF has been evaluated by simulation. Furthermore, we fabricated the RS-FF using a Nb/AlOx/Nb junction technology and demonstrated its operation experimentally.
Scientific journal, English

IMPLEMENTATION OF SUPERCONDUCTING SYNAPSES INTO A NEURON-BASED ANALOG-TO-DIGITAL CONVERTER
Y MIZUGAKI; K NAKAJIMA; Y SAWADA; T YAMASHITA
APPLIED PHYSICS LETTERS, AMER INST PHYSICS, 65, 13, 1712-1713, Sep. 1994, Peer-reviwed, A superconducting synapse circuit, which allows digitally variable synaptic weights, is presented. Each bit of the synapse circuit consists of 2(m) ((m=0, 1, 2,...) double-junction SQUIDs !superconducting quantum interference devices). Numerical simulation shows that the output current of the circuit can be changed digitally by switching the bias currents. To demonstrate this ability of the synapse experimentally, a superconducting neural network which functions as a 3-bit A/D (analog-to-digital) converter has been fabricated using a niobium integration technology. The network contains three neurons composed of coupled SQUIDs and three synapses composed of double-junction SQUIDs. This is the first successful implementation of such an active synapse into a superconducting neural network.
Scientific journal, English

New Approach to Hardware Implementation of Neural Circuits Using Superconductive Devices
Y. Mizugaki; K. Nakajima; Y. Sawada; T. Yamashita
Proc. 1994 Int. Conf. Solid State Devices and Materials, 364-366, Aug. 1994, Peer-reviwed
International conference proceedings, English

IMPLEMENTATION OF NEW SUPERCONDUCTING NEURAL CIRCUITS USING COUPLED SQUIDS
Y MIZUGAKI; K NAKAJIMA; Y SAWADA; T YAMASHITA
IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 4, 1, 1-8, Mar. 1994, Peer-reviwed, A novel superconducting neuron circuit and two types,of variable synapses; which are based on superconducting quantum interferometer devices (SQUIDs), are presented. A neuron circuit with good input-output isolation and steep threshold characteristics is accomplished using a combination of a single-junction SQUID coupled to a double-junction SQUID. The quantum state of the single-junction SQUID represents the neuron state, and the output voltage of the double-junction SQUID, which is operated in a nonlatching mode with shunt resistors, is a sigmoid-shaped function of the input. Both variable synapse. circuits are composed of multiple shunted double-junction SQUIDs. The first type changes its conductance value by using both superconducting and voltage states. The second variable synapse circuit changes its output current digitally by switching its bias currents. Besides numerical simulations of the circuit characteristics, we have fabricated superconducting neural chips in a Nb/AlOx/Nb Josephson junction technology. The fundamental operation of each element and a 2-bit neural-based A/D converter have been successfully tested. A learning system with a variable synapse is also discussed.
Scientific journal, English

Superconducting Implementation of Neural Netowrks Using Nb/AlO_x_/Nb Josephson Junctions
Y. Mizugaki; K. Nakajima; Y. Sawada; T. Yamashita
Proc. Int. Conf. Advanced Microelectronic Devices and Processing, 655-660, Mar. 1994, Peer-reviwed
International conference proceedings, English

結合SQUIDによる超伝導薄膜のカイネティックインダクタンスの研究
小野美 武; 水柿義直; 中島康治; 山下努
東北大学電通談話会記録, 東北大学電気通信研究所工学研究会, 62, 2, 283-287, Mar. 1994, Peer-reviwed
Research institution, Japanese

Superconducting Implementation of Neural Networks
Y. Mizugaki; K. Nakajima; Y. Sawada; T. Yamashita
Proc. 1993 Int. Symp. Nonlinear Theory and Its Applications, 1, 193-198, Dec. 1993, Peer-reviwed
International conference proceedings, English

Novel Superconducting Neuron and Synapse
Y. Mizugaki; K. Nakajima; Y. Sawada; T. Yamashita
Advances in Superconductivity VI (Proc. 6th Int. Symp. Superconductivity), 2, 1203-1206, Oct. 1993, Peer-reviwed
International conference proceedings, English

LINEARIZATION ANALYSIS OF THRESHOLD CHARACTERISTICS FOR SOME APPLICATIONS OF MUTUALLY COUPLED SQUIDS
Y MIZUGAKI; K NAKAJIMA; T YAMASHITA
IEICE TRANSACTIONS ON ELECTRONICS, IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG, E76C, 8, 1291-1297, Aug. 1993, Peer-reviwed, The threshold characteristics of mutually coupled SQUIDs (Superconducting Quantum Interference Devices) have been analytically and numerically investigated. The mutually coupled SQUIDs investigated is composed of an rf-SQUID and a dc-SQUID. Here, the rf-SQUID is a flux quantum generator and the dc-SQUID is a flux detector. The linearization method substituting sin-1x by (pi/2)x (-1 less-than-or-equal-to x less-than-or-equal-to +1) is found valid when it is applied to the mutually coupled SQUIDs, because it is possible to obtain the superconducting regions analytically. By computer implementation of linearization method, we found this method is very effective and very quick compared to the ordinary methods. We report the internal flux of an rf-SQUID. the threshold of a dc-SQUID, and that of mutually coupled SQUIDs obtained by Lagrange multiplier formulation and linearization. The features of the threshold characteristics of the mutually coupled SQUIDs with various parameters are also reported. The discontinuous behavior of threshold of the mutually coupled SQUIDs are attractive for digital applications. We suggest three applications of the mutually coupled SQUIDs, that is, a logic gate for high-T(c) superconductors (HTSs), a neuron device, and an A/D converter.
Scientific journal, English

SUPERCONDUCTING IMPLEMENTATION OF NEURAL NETWORKS USING FLUXON PULSES
Y. Mizugaki; K. Nakajima; Y. Sawada; T. Yamashita
IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY, IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 3, 1, 2765-2768, Mar. 1993, Peer-reviwed, We fabricated neural-based superconducting integrated-circuits by using Nb/AlOx/Nb Josephson junctions, and demonstrated the operation of 2-bit neural based A/D converter which is one of the circuits solving optimization problems. We used fluxon pulses as neural impulses and a Josephson junction as a threshold element. The conductance values of resistors by which Josephson transmission lines are connected represent fixed synaptic strengths. The preliminary experimental result suggests that variable critical currents of dc-SQUID may provide synapses with variable strength.
Scientific journal, English

SUPERCONDUCTING NEURAL CIRCUITS USING FLUXON PULSES
Y MIZUGAKI; K NAKAJIMA; Y SAWADA; T YAMASHITA
APPLIED PHYSICS LETTERS, AMER INST PHYSICS, 62, 7, 762-764, Feb. 1993, Peer-reviwed, A superconducting neural circuit is fabricated for the first time by use of a niobium integrated-circuit technology. Fluxon pulses on Josephson transmission lines (JTLs) are used as neural impulses. In this circuit a threshold element (a neuron) is composed of two JTL elements connected through a resistor. The conductance value of the resistor represent a synaptic strength. The fan-in and the fan-out are accomplished by the biased JTL branches. The operation of 2-bit neural based A/D converter is successfully observed. These circuits do not require any hysteretic Josephson junctions, and hence, have a potential to be fabricated with the high-T(c) superconductors.
Scientific journal, English

SUPERCONDUCTING IMPLEMENTATION OF NEURAL NETWORKS USING FLUXON PULSES
Y MIZUGAKI; K NAKAJIMA; Y SAWADA; T YAMASHITA
IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY, VOL 3, NO 1, MARCH 1993 PTS 2-4, I E E E, 2765-2768, 1993
International conference proceedings, English

Superconducting neural computer
K. Nakajima; Y. Mizugaki; T. Yamashita; Y. Sawada
Applied Superconductivity, 1, 10-12, 1893-1905, 1993, Peer-reviwed, We fabricated neural-based superconducting integrated-circuits by using Nb/AlOx/Nb Josephson junctions, and demonstrated circuit operation of 2-bit neural-based A/D converter as an example of optimization problem. We used, in the present superconducting neural circuits, fluxon pulses as the neural impulses and a Josephson junction as a threshold element to achieve an advanced operation. The integrative time delays due to the inductance of superconducting circuits correspond to those due to capacitance in real neurons. The values of resistor by which Josephson transmission lines are connected represent fixed synaptic strengthes. The preliminary experimental result suggests that variable critical currents of d.c. SQUID may provide synapses with variable strength. In our implementation scheme, complex circuit design can easily be realized by connecting Josephson transmission lines. In order to design complex circuits like a Hopfield neural network, we propose a new method which can be used to analyze the properties of local minima in the energy function. A novel design technique to eliminate these local minima in the networks has been developed. It is useful for hardware studies on artificial neural networks using superconductor and semiconductor. © 1993.
Scientific journal, English

Superconducting neural computer
K. Nakajima; Y. Mizugaki; T. Yamashita; Y. Sawada
Applied Superconductivity, 1, 10-12, 1893-1905, 1993, Peer-reviwed, We fabricated neural-based superconducting integrated-circuits by using Nb/AlOx/Nb Josephson junctions, and demonstrated circuit operation of 2-bit neural-based A/D converter as an example of optimization problem. We used, in the present superconducting neural circuits, fluxon pulses as the neural impulses and a Josephson junction as a threshold element to achieve an advanced operation. The integrative time delays due to the inductance of superconducting circuits correspond to those due to capacitance in real neurons. The values of resistor by which Josephson transmission lines are connected represent fixed synaptic strengthes. The preliminary experimental result suggests that variable critical currents of d.c. SQUID may provide synapses with variable strength. In our implementation scheme, complex circuit design can easily be realized by connecting Josephson transmission lines. In order to design complex circuits like a Hopfield neural network, we propose a new method which can be used to analyze the properties of local minima in the energy function. A novel design technique to eliminate these local minima in the networks has been developed. It is useful for hardware studies on artificial neural networks using superconductor and semiconductor. © 1993.
Scientific journal, English

SUPERCONDUCTING IMPLEMENTATION OF NEURAL NETWORKS USING FLUXON PULSES
Y MIZUGAKI; K NAKAJIMA; Y SAWADA; T YAMASHITA
IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY, VOL 3, NO 1, MARCH 1993 PTS 2-4, I E E E, 3, 1, 2765-2768, 1993, Peer-reviwed
International conference proceedings, English

超伝導神経回路網の構成に関する基礎的研究
水柿義直
東北大学電通談話会記録, 61, 1, 201-202, Jul. 1992
Research institution, Japanese

Characteristics of Nb-AlO_x_-Nb Junctions Fabricated by a New Simple Integration Process
水柿義直; 中島康治; 澤田康次; 山下努
The Transactions of the Institute of Electronics, Information and Communication Engineers, 電子情報通信学会エレクトロニクスソサイエティ, Vol. J74-C-II, 12, 812-814, Dec. 1991, Peer-reviwed
Scientific journal, Japanese

Two kinds of single electron devices fabricated by dispersion of gold nano particles with different diameter
守屋 雅隆; Tran Thi Thu Huong; 松本 和彦; 島田 宏; 木村 康男; 平野 愛弓; 水柿 義直
電子情報通信学会, 21 Apr. 2016, 電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, 116, 14, 21-26, Japanese, 0913-5685, 40020819023, AN10012954

C-8-15 9-bit, 2.5-mV_ superconductive single-flux-quantum digital-to-analog converter based on SFQ pulse-frequency modulation
Mizugaki Yoshinao; Takahashi Yoshitaka; Shimada Hiroshi; Maezawa Masaaki
The Institute of Electronics, Information and Communication Engineers, 09 Sep. 2014, Proceedings of the Society Conference of IEICE, 2014, 2, 29-29, Japanese, 110009882211, AN10489017

Prototypes of Single-Chip Voltage Waveform Generators Based on SFQ Pulse-Frequency Modulation
MIZUGAKI Yoshinao; KUROIWA Keisuke; SATO Yusuke; TAKAHASHI Yoshitaka; SHIMADA Hiroshi; MAEZAWA Masaaki
We have been developing single-chip voltage waveform generators based on single-flux-quantum (SFQ) pulse-frequency modulation (PFM). They comprise an SFQ-PFM digital-to-analog converter integrated with a code generator on the same chip. Code generators are designed for specified waveforms such as a sinusoidal wave and a triangle wave. Although their resolutions at the current moment are limited to 6 bits, operation of several voltage waveform generators has been demonstrated using a niobium SFQ digital technology., The Institute of Electronics, Information and Communication Engineers, 23 Jul. 2014, Technical report of IEICE. SCE, 114, 147, 43-46, English, 0913-5685, 110009946823, AN10012885

Zero-crossing Shapiro steps generated in a Josephson junction having asymmetric magnetic field response
TAKAHASHI Haruna; MORIYA Masataka; TOKUYAMA Takato; SHIMADA Hiroshi; MIZUGAKI Yoshinao
In current DC voltage standards, Shapiro steps across the zero bias current axis (Zero-crossing Shapiro steps) have been already used, and they are expected to be applied for high-precision D / A converters. We have studied asymmetric 2-junction SQUIDs generating a Zero-crossing Shapiro step. It is based on using their asymmetric critical current - magnetic field characteristics obtained. In this report, instead of on asymmetric 2-junction SQUID, large Josephson junctons with asymmetric critical current - magnetic field characteristics are employed for generating a Zero-crossing Shapiro step. We demonstrate Zero-crossing Shapiro steps using a Nb/AlO_x/Nb tunnel junction and a YBa_2Cu_3O_<7_δ> grain boundary junction., The Institute of Electronics, Information and Communication Engineers, 23 Jan. 2014, Technical report of IEICE. SCE, 113, 401, 13-18, Japanese, 0913-5685, 110009822114, AN10012885

Dual Aspects of the Quantum Current-Mirror Effect in Arrays of Small Josephson Junctions
Shimada Hiroshi; Takeda Koichi; Mizugaki Yoshinao
The Institute of Electronics, Information and Communication Engineers, 03 Sep. 2013, Proceedings of the Society Conference of IEICE, 2013, 2, 19-19, Japanese, 110009735798, AN10489017

Small-Current Multiplier Based on the Quantum Current-Mirror Effect
Takeda Kouichi; Mizugaki Yoshinao; Shimada Hiroshi
The Institute of Electronics, Information and Communication Engineers, 03 Sep. 2013, Proceedings of the Society Conference of IEICE, 2013, 2, 20-20, Japanese, 110009735799, AN10489017

C-8-16 3-bit Bipolar D/A converter comprising Balanced-Ternary-weighted Array of 2J-SQUIDs
Mizugaki Yoshinao; Moriya Masataka; Takizawa Hiroyuki
The Institute of Electronics, Information and Communication Engineers, 05 Mar. 2013, Proceedings of the IEICE General Conference, 2013, 2, 47-47, Japanese, 110009767085, AN10471452

C-8-15 Multiplication Accuracy of 1000-Fold voltage Multiplier integrated with DC/SFQ Converter
Sato Yusuke; Moriyai Masataka; Shimada Hiroshi; Mizugaki Yoshinao; Maezawa Masaaki
The Institute of Electronics, Information and Communication Engineers, 05 Mar. 2013, Proceedings of the IEICE General Conference, 2013, 2, 46-46, Japanese, 110009767084, AN10471452

C-8-17 Single Cooper-pair devices based on Al/AlO_x/V Josephson jmctions
Miyawaki Kenji; Hagihara Ayano; Kotani Sachio; Mizugaki Yoshinao; Shimada Hireshi
The Institute of Electronics, Information and Communication Engineers, 05 Mar. 2013, Proceedings of the IEICE General Conference, 2013, 2, 48-48, Japanese, 110009767086, AN10471452

Blocking Oscillation Using Combination of Discrete and Continuous Charge/Flux Transfer in Dissipative Single-Quantum Devices
MIZUGAKI Yoshinao
The island charge of a single-electron (SE) transistor is discrete because of SE tunneling through tiny tunnel junctions. The loop flux of a superconducting quantum interference device (SQUID) is also discrete because of single-flux-quantum (SFQ) transition through Josephson junctions. We report that blocking oscillators (BOs) are realized by introducing dissipative elements (resistors) into SE transistors and SQUIDs. An SE-BO is composed of an SE transistor with a resistor shunting between the island and ground. By voltage-biasing slightly higher than the Coulomb blockade threshold, intermittent SE tunneling events occur. On the other hand, an SFQ-BO is composed of a SQUID with a resistor inserted in the superconducting loop. By current-biasing slightly higher than the superconducting critical current, intermittent SFQ transitions occur. We demonstrate numerical results of these blocking oscillation phenomena. Although the SE-BO and SFQ-BO are electromagnetically dual, the numerical results show some differences between their properties. We also present numerical demonstration for applications of SFQ-BOs, as well as experimental results showing the SFQ-BO operation., The Institute of Electronics, Information and Communication Engineers, 27 Feb. 2013, IEICE technical report. Electron devices, 112, 445, 59-64, Japanese, 0913-5685, 110009728442, AN10012954

Correlation between polarity of magnetoresistance ratio and tunnel resistance in ferromagnetic SET with superconductive island
TAKIGUCHI Masashi; MORIYA Masataka; SHIMADA Hiroshi; MIZUGAKI Yoshinao
Negative magnetoresistance ratio is shown in ferromagnet-superconductor-ferromagnet double tunnel junctions. An excessive spin accumulation in a superconductor produces the suppression of the superconductivity. Since the spin will be relaxed by time in a superconductor, more injection of spin-polarized quasiparticles from the ferromagnetic leads to the super-conductor are required to obtain the negative magnetoresistance ratio. The spin injection rate is driven by the tunnel resistance. It is predicted that the polarity of tunnel resistance and a magnetic resistance ratio has as negative correlation. We fabricated several ferromagnetic SET with superconductive island, and measured the correlation between the polarity of a magnetore-sistance ratio and the tunnel resistance. The samples which have the lower tunnel resistance showed the negative magnetore-sistance ratio, and other samples which have the higher tunnel resistance showed the positive magnetoresistance ratio. Our experimental results have an agreement with the prediction., The Institute of Electronics, Information and Communication Engineers, 27 Feb. 2013, IEICE technical report. Electron devices, 112, 445, 65-70, Japanese, 0913-5685, 110009728443, AN10012954

Relaxation oscillation in single-quantum-tunneling devices and its application to information processing
水柿 義直
旭硝子財団, 2013, 旭硝子財団助成研究成果報告, 1-6, Japanese, 1882-0069, 40019977771

C-8-3 Effects of Charging Energy on Quantum Interference Pattern of DC-SQUID Comprising Two Sub-Micron Aluminum Josephson Junctions
Mizugaki Yoshinao; Kikuchi Kento; Shimada Hiroshi
The Institute of Electronics, Information and Communication Engineers, 28 Aug. 2012, Proceedings of the Society Conference of IEICE, 2012, 2, 39-39, Japanese, 110009593830, AN10489017

C-8-2 Temperature Dependence of Magneto Resistance Ratio in Ferromagnetic-Superconductor-Ferromagnetic Single-Electron Transistor
Takiguchi Masashi; Shimada Hiroshi; Moriya Masataka; Mizugaki Yoshinao
The Institute of Electronics, Information and Communication Engineers, 28 Aug. 2012, Proceedings of the Society Conference of IEICE, 2012, 2, 38-38, Japanese, 110009593829, AN10489017

C-8-7 Bipolar D/A converter based on zero-crossing Shapiro steps in asymmetric 2J-SQUIDs
Moriya Masataka; Takizawa Hiroyuki; Mizugaki Yoshinao
The Institute of Electronics, Information and Communication Engineers, 06 Mar. 2012, Proceedings of the IEICE General Conference, 2012, 2, 34-34, Japanese, 110009459297, AN10471452

24aBJ-2 Current induction between arrays of small Josephson junctions
Ishida Chihiro; Mizugaki Yoshinao; Shimada Hiroshi
The Physical Society of Japan (JPS), 05 Mar. 2012, Meeting abstracts of the Physical Society of Japan, 67, 1, 717-717, Japanese, 1342-8349, 110009567457, AA11439205

Invited : Voltage Waveform Synthesizer Based on SFQ Pulse Frequency Modulation
KUROIWA Keisuke; MORIYA Masataka; SHIMADA Hiroshi; MIZUGAKI Yoshinao; MAEZAWA Masaaki
A digital-to-analog converter based on single flux quantum (SFQ) circuits (RSFQ-DAC) is a candidate for ac voltage standards. Recently, we have proposed an RSFQ-DAC based on SFQ pulse frequency modulation, where the frequency of SFQ pulse train is changed by a Variable-Pulse Number Multiplier (V-PNM). For demonstration of the RSFQ-DAC based on SFQ pulse frequency modulation, we designed and tested voltage waveform synthesizers connected with a circuit that generates digital codes. In this report, we describe the operation of voltage waveform synthesizers based on SFQ pulse frequency modulation., The Institute of Electronics, Information and Communication Engineers, 26 Jan. 2012, Technical report of IEICE. SCE, 111, 418, 17-22, Japanese, 0913-5685, 110009480946, AN10012885

自己抑制型誘電泳動法による金ナノ粒子捕獲時のインピーダンス変化
飯沼惟人; 林 優生; 島田 宏; 水柿義直
Oral presentation, 電子情報通信学会 電子部品・材料(CPM)研究会
28 Feb. 2025
28 Feb. 2025- 28 Feb. 2025

Time-to-Digital Converter を導入したSFQ All-Digital Phase-Locked Loopの設計と評価
福代大紀; 島田 宏; 水柿義直
Invited oral presentation, 電子情報通信学会 超伝導エレクトロニクス(SCE)研究会, Invited
14 Jan. 2025
14 Jan. 2025- 14 Jan. 2025

Design of an RSFQ All-Digital Phase Locked Loop with a Time-to-Digital Converter
D. Fukuyo; H. Shimada; Y. Mizugaki
Oral presentation, English, 37th International Symposium on Superconductivity (ISS 2024), Peer-reviewed
05 Dec. 2024
03 Dec. 2024- 05 Dec. 2024

Design of a microwave generator as an application of an SFQ pulse-frequency modulation digital-to-analog converter
Y. Mizugaki; S. Hayashi; H. Shimada
Oral presentation, English, 37th International Symposium on Superconductivity (ISS 2024), Peer-reviewed
03 Dec. 2024
03 Dec. 2024- 05 Dec. 2024

Information processing in Coulomb-blockade-based gold-nanoparticle reservoirs connected in parallel
Y. Hayashi; H. Shimada; Y. Mizugaki
Poster presentation, English, 37th International Microprocesses and Nanotechnology Conference (MNC 2024), Peer-reviewed
14 Nov. 2024
12 Nov. 2024- 15 Nov. 2024

Microwave Generator Designed Based on Direct Digital Synthesis with SFQ Pulse-Frequency Modulation D/A Converter
Y. Mizugaki; S. Hayashi; H. Shimada
Oral presentation, English, 17th Superconducting SFQ VLSI Workshop (SSV 2024)
11 Oct. 2024
11 Oct. 2024- 12 Oct. 2024

超伝導デバイスを用いたSiO2/Si界面を持つSiO2層のフォノン減衰調の測定
飯塚竜也; J. Tanarom; 水柿義直; 島田 宏
Oral presentation, Japanese, 第85回応用物理学会秋季学術講演会
19 Sep. 2024
16 Sep. 2024- 20 Sep. 2024

クーロン閉塞を利用する金ナノ粒子リザバーの並列化による性能向上
林 優生; 小林海斗; 島田 宏; 水柿義直
Oral presentation, Japanese, 第85回応用物理学会秋季学術講演会
16 Sep. 2024
16 Sep. 2024- 20 Sep. 2024

遠隔配置した微小ジョセフソン接合列間のフォトンを介した電流相関
塩田雄太; 飯塚竜也; 水柿義直; 島田 宏
Oral presentation, Japanese, 日本物理学会 第79回年次大会
17 Sep. 2024
16 Sep. 2024- 19 Sep. 2024

多段階コロイド液浸法で作製した金ナノ粒子集合体の液体窒素温度での物理リザバー動作
小林海斗; 林 優生; 島田 宏; 水柿義直
Oral presentation, Japanese, 第85回応用物理学会秋季学術講演会
16 Sep. 2024
16 Sep. 2024- 19 Sep. 2024

Time-to-Digital Converter の改良による SFQ All-Digital Phase Locked Loop の位相誤差の低減
福代大紀; 島田 宏; 水柿義直
Oral presentation, Japanese, 電子情報通信学会ソサイエティ大会
12 Sep. 2024
10 Sep. 2024- 13 Sep. 2024

クーロン閉塞を発現する金ナノ粒子集合体を物理リザバーに用いた波形分類実験,
林 優生; 小林海斗; 守屋雅隆; 島田 宏; 水柿義直
Poster presentation, Japanese, 第71回応用物理学会春季学術講演会
23 Mar. 2024
22 Mar. 2024- 25 Mar. 2024

Time-to-Digital Converterを備えたSFQ All-Digital Phase Locked Loopの設計
福代大紀; 島田 宏; 水柿義直
Oral presentation, Japanese, 電子情報通信学会総合大会
06 Mar. 2024
04 Mar. 2024- 08 Mar. 2024

Coulomb-Blockade-Based Nonlinear Signal Conversion in Gold-Nanoparticle Random Arrays
Y. Mizugaki; K. Fujikura; H. Shimada
Oral presentation, English, 14th International Workshop on Nanostructures & Nanoelectronics (IWNN-14)
Mar. 2024
05 Mar. 2024- 06 Mar. 2024

Physical reservoir made of gold-nanoparticle random arrays exhibiting nonlinear characteristics due to the Coulomb blockade
Y. Hayashi; K. Kobayashi; M. Moriya; H. Shimada; Y. Mizugaki
Poster presentation, English, 12th RIEC International Symposium on Brain Functions and Brain Computer (BFBC 2024)
27 Feb. 2024
27 Feb. 2024- 28 Feb. 2024

単一磁束量子パルス周波数変調型D/A変換器のGHz信号生成回路への応用
林 誠也; 島田 宏; 水柿義直
Oral presentation, Japanese, 電子情報通信学会技術研究報告（超伝導エレクトロニクスSCE）
23 Jan. 2024
23 Jan. 2024- 23 Jan. 2024

Siチップのアパーチャに形成した自立型脂質二分子膜の定電流経時測定
嶋田佳宏; 守屋雅隆; 島田 宏; 但木大介; 平野愛弓; 水柿義直
Oral presentation, Japanese, 電子情報通信学会技術研究報告（電子部品・材料研究会CPM）
08 Dec. 2023
08 Dec. 2023- 09 Dec. 2023

Development of RSFQ digital-to-analog converters generating quantum voltages
Y. Mizugaki
Invited oral presentation, English, 36th International Symposium on Superconductivity (ISS2023), Invited, Peer-reviewed
30 Nov. 2023
28 Nov. 2023- 30 Nov. 2023

Physical Reservoir Application of Random Network of Gold Nanoparticles Fabricated by Multi-Step Immersion in Gold Colloidal Solution,
K. Kobayashi; Y. Hayashi; K. Fujikura; M. Moriya; H. Shimada; Y. Mizugaki
Poster presentation, English, 36th International Microprocesses and Nanotechnology Conference (MNC 2023), Peer-reviewed
17 Nov. 2023
14 Nov. 2023- 17 Nov. 2023

SiO2/Si基板上の超伝導デバイス間におけるフォノン伝播の研究
飯塚竜也; 水柿義直; 島田 宏
Oral presentation, 第84回応用物理学会秋季学術講演会
21 Sep. 2023
19 Sep. 2023- 23 Sep. 2023

単一磁束量子パルス周波数変調型マイクロ波発生器の設計
林 誠也; 島田 宏; 水柿義直
Oral presentation, 第84回応用物理学会秋季学術講演会
21 Sep. 2023
19 Sep. 2023- 23 Sep. 2023

Si/Si3N4チップのアパーチャに形成した自立型脂質二分子膜の定電流経時測定
嶋田佳宏; 平松大樹; 守屋雅隆; 島田 宏; 但木大介; 平野愛弓; 水柿義直
Poster presentation, 第84回応用物理学会秋季学術講演会
20 Sep. 2023
19 Sep. 2023- 23 Sep. 2023

多段階液浸法で作製した金ナノ粒子ランダム配列の物理リザバー応用
小林海斗; 林 優生; 藤倉健太; 守屋雅隆; 島田 宏; 水柿義直
Poster presentation, 第84回応用物理学会秋季学術講演会
20 Sep. 2023
19 Sep. 2023- 23 Sep. 2023

Numerical study on physical reservoir computing with Josephson junctions
K. Watanabe; Y. Mizugaki; S. Moriya; H. Yamamoto; T. Yamashita; S. Sato
Poster presentation, 16th European Conference on Applied Superconductivity (EUCAS2023), Peer-reviewed
05 Sep. 2023
03 Sep. 2023- 07 Sep. 2023

RSFQ Hardware Random Number Generator Comprising Two Josephson Oscillators
Y. Mizugaki; K. Sato; H. Shimada
Oral presentation, 16th European Conference on Applied Superconductivity (EUCAS2023), Peer-reviewed
04 Sep. 2023
03 Sep. 2023- 07 Sep. 2023

Random Number Generation Utilizing Timing Jitters of Single-Flux-Quantum Propagation
Y. Mizugaki; K. Sato; H. Shimada; T. Onomi
Oral presentation, The 44th PhotonIcs and Electromagnetics Research Symposium (PIERS2023), Peer-reviewed
05 Jul. 2023
03 Jul. 2023- 06 Jul. 2023

Nonlinear Signal Conversion in Gold-Nanoparticle Random Array for Physical Reservoir Applications
Y. Mizugaki; K. Fujikura; H. Shimada
Oral presentation, The 9th International Symposium on Organic and Inorganic Electronic Materials and Related Nanotechnologies (EM-NANO2023), Peer-reviewed
08 Jun. 2023
05 Jun. 2023- 08 Jun. 2023

Voltage-Swing Improvement of Double-SQUID Amplifier by Tuning McCumber Parameter
S. Hayashi; N. Sega; K. Sato; Y. Mizugaki
Poster presentation, 11th East Asia Symposium on Superconductor Electronics (EASSE 2023)
27 Mar. 2023
27 Mar. 2023- 29 Mar. 2023

Development of SFQ Oscillator-Based Hardware Random Number Generators
Y. Mizugaki; K. Sato; T. Onomi
Invited oral presentation, 11th East Asia Symposium on Superconductor Electronics (EASSE 2023), Invited
27 Mar. 2023
27 Mar. 2023- 29 Mar. 2023

単一Cooper 対トランジスタによるフォノンの高感度検出
島田 宏; Jutarat Tanarom; 水柿義直
Oral presentation, 第70回応用物理学会春季学術講演会
17 Mar. 2023
15 Mar. 2023- 18 Mar. 2023

2次元接続されたジョセフソン接合を用いたリザバー計算の画像分類応用における性能について
渡邊紘基; 水柿義直; 守谷 哲; 山本英明; 佐藤茂雄
Oral presentation, 第70回応用物理学会春季学術講演会
16 Mar. 2023
15 Mar. 2023- 18 Mar. 2023

Nonlinear Responses Observed in Random Arrays of Gold Nanoparticles Assembled by Dielectrophoresis
Y. Mizugaki; T. Urae; H. Shimada
Oral presentation, 13th International Workshop on Nanostructures & Nanoelectronics
08 Mar. 2023
07 Mar. 2023- 08 Mar. 2023

微細素子静電強結合のための原子層堆積TiO2膜の研究
高田文洋; 水柿義直; 島田 宏
Oral presentation, 電子情報通信学会技術研究報告（電子部品・材料研究会）
28 Feb. 2023
28 Feb. 2023- 28 Feb. 2023

2種類の粒径の金ナノ粒子集合体での高周波誘起電流の観測
林 優生; 小林海斗; 藤倉健太; 島田 宏; 水柿義直
Oral presentation, 電子情報通信学会技術研究報告（電子部品・材料研究会）
28 Feb. 2023
28 Feb. 2023- 28 Feb. 2023

自立型DPPC膜の繰り返しEIS測定から抽出した特性容量の温度依存性
上田翔弥; 嶋田佳宏; 平松大樹; 守屋雅隆; 但木大介; 平野愛弓; 水柿義直
Oral presentation, 電子情報通信学会技術研究報告（電子部品・材料研究会）
28 Feb. 2023
28 Feb. 2023- 28 Feb. 2023

Parameter optimization of two-dimensionally connected Josephson junctions for reservoir computing
K. Watanabe, Y. Mizugaki, S. Moriya, H. Yamamoto, and S. Sato
Poster presentation, English, The 11th RIEC International Symposium on Brain Functions and Brain Computer (BFBC 2023), Research Institute of Electrical Communication, Tohoku University, Sendai, Japan
18 Feb. 2023
17 Feb. 2023- 18 Feb. 2023

Evaluation of True Random Number Sequences Generated by Utilizing Timing Jitters in Superconducting Integrated Circuits
K. Sato; N. Sega; H. Shimada; Y. Mizugaki
Oral presentation, English, 35th International Symposium on Superconductivity (ISS 2022), Nagoya & on-line, Peer-reviewed, International conference
01 Dec. 2022
29 Nov. 2022- 01 Dec. 2022

Equivalent circuit analysis of AC impedance fluctuation measured across free-standing bilayer lipid membranes mixed with carbon nanotubes
D. Hiramatsu; R. Sato; M. Moriya; H. Shimada; D. Tadaki; A. Hirano-Iwata; Y. Mizugaki
Poster presentation, English, 35th International Microprocesses and Nanotechnology Conference (MNC 2022), JSAP, Tokushima, Peer-reviewed, International conference
10 Nov. 2022
08 Nov. 2022- 11 Nov. 2022

Microcontroller-Controlled Dielectrophoretic Assembly of Gold Nanoparticle Arrays toward Realization of Physical Reservoir Devices
Y. Mizugaki; T. Urae; H. Shimada
Poster presentation, English, 35th International Microprocesses and Nanotechnology Conference (MNC 2022), JSAP, Tokushima, Peer-reviewed, International conference
10 Nov. 2022
08 Nov. 2022- 11 Nov. 2022

タイミングジッタを利用して真性乱数を生成する超伝導集積回路の評価
佐藤健太; 瀬賀直功; 島田 宏; 水柿義直
Oral presentation, Japanese, 電子情報通信学会技術研究報告（超伝導エレクトロニクス）, 電子情報通信学会, 仙台, Domestic conference
04 Nov. 2022
04 Nov. 2022- 04 Nov. 2022

稀釈冷凍温度で動作するラテラル型過減衰Al/AlOx/Al接合の作製
星野将弥; 水柿義直; 島田 宏
Oral presentation, Japanese, 電子情報通信学会技術研究報告（超伝導エレクトロニクス）, 電子情報通信学会, 仙台, Domestic conference
04 Nov. 2022
04 Nov. 2022- 04 Nov. 2022

Sensitive phonon detection by use of a single Cooper-pair transistor
H. Shimada; J. Tanarom; T. Watanabe; T. Iizuka; Y. Mizugaki
Poster presentation, English, Applied Superconductivity Conference (ASC2022), Peer-reviewed, International conference
24 Oct. 2022
23 Oct. 2022- 28 Oct. 2022

Optimization of circuit parameters for JTL-based reservoir computing
K. Watanabe; Y. Mizugaki; S. Moriya; H. Yamamoto; S. Sato
Poster presentation, English, The 2022 JSPS 146th Committee International Symposium on Superconductor Electronics jointed with 15th Superconducting SFQ VLSI Workshop (SSV 2022) and 4th Workshop on Quantum and Classical Cryogenic Devices, Circuits, and Systems (QCCC 2022), JSPS, Kyoto, International conference
30 Sep. 2022
28 Sep. 2022- 30 Sep. 2022

Voltage-Swing Values of Double-SQUID amplifiers having various McCumber parameters
S. Hayashi; N. Sega; K. Sato; Y. Mizugaki
Poster presentation, English, The 2022 JSPS 146th Committee International Symposium on Superconductor Electronics jointed with 15th Superconducting SFQ VLSI Workshop (SSV 2022) and 4th Workshop on Quantum and Classical Cryogenic Devices, Circuits, and Systems (QCCC 2022), JSPS, Kyoto, International conference
30 Sep. 2022
28 Sep. 2022- 30 Sep. 2022

Hardware Random Number Generator Utilizing Timing Jitters in RSFQ Logic Circuits
Y. Mizugaki; K. Sato; N. Sega; Y. Somei; H. Shimada; T. Onomi
Oral presentation, English, The 2022 JSPS 146th Committee International Symposium on Superconductor Electronics jointed with 15th Superconducting SFQ VLSI Workshop (SSV 2022) and 4th Workshop on Quantum and Classical Cryogenic Devices, Circuits, and Systems (QCCC 2022), JSPS, Kyoto, International conference
28 Sep. 2022
28 Sep. 2022- 30 Sep. 2022

誘電泳動による金ナノ粒子配列形成時の電極間インピーダンス測定
浦江哲也; 島田 宏; 水柿 義直
Oral presentation, Japanese, 第83回応用物理学会秋季学術講演会, 応用物理学会, 仙台＆オンライン, Domestic conference
21 Sep. 2022
20 Sep. 2022- 23 Sep. 2022

CNTを混合した自立型脂質二分子膜で観測される交流インピーダンス繰り返し増減の等価回路解析
平松大樹; 佐藤 陸; 守屋雅隆; 島田 宏; 但木大介; 平野愛弓; 水柿義直
Oral presentation, Japanese, 第83回応用物理学会秋季学術講演会, 応用物理学会, 仙台＆オンライン, Domestic conference
21 Sep. 2022
20 Sep. 2022- 23 Sep. 2022

物理リザバーを目指した炭素被覆Coナノ粒子集合体での非線形信号変換
藤倉健太; 浦江哲也; 守屋雅隆; 島田 宏; 水柿義直
Poster presentation, Japanese, 第83回応用物理学会秋季学術講演会, 応用物理学会, 仙台＆オンライン, Domestic conference
20 Sep. 2022
20 Sep. 2022- 23 Sep. 2022

２つのオシレータのタイミングジッタを利用するRSFQ 真性乱数生成回路の動作実証
佐藤健太; 瀬賀直功; 島田 宏; 水柿義直
Oral presentation, Japanese, 電子情報通信学会ソサイエティ大会, 電子情報通信学会, Domestic conference
07 Sep. 2022
06 Sep. 2022- 09 Sep. 2022

Phonon Detection with a Supercurrent through a Single Cooper-Pair Transistor
H. Shimada; J. Tanarom; T. Watanabe; T. Iizuka; Y. Mizugaki
Poster presentation, English, 29th International Conference on Low Temperature Physics (LT29), Sapporo and on-line, Peer-reviewed, International conference
22 Aug. 2022
18 Aug. 2022- 24 Aug. 2022

波形分類のためのジョセフソン伝送線路を用いた物理リザバー
渡邊紘基; 水柿義直; 守谷 哲; 山本英明; 佐藤茂雄
Oral presentation, Japanese, 電子情報通信学会技術研究報告（超伝導エレクトロニクス）, 電子情報通信学会, 横浜＆オンライン, Domestic conference
09 Aug. 2022
09 Aug. 2022- 09 Aug. 2022

自立型平面脂質二分子膜の交流特性測定で観測された非線形応答
冨岡康貴; 守屋雅隆; 高島匠吾; 島田 宏; 廣瀬文彦; 平野愛弓; 水柿義直
Oral presentation, Japanese, 電子情報通信学会技術研究報告（電子デバイス）, 電子情報通信学会, オンライン, Domestic conference
21 Apr. 2022
21 Apr. 2022- 21 Apr. 2022

炭素系ナノ材料を混合した自立型脂質二分子膜の電気的特性
佐藤 陸; 平田はるか; 守屋雅隆; 島田 宏; 但木大介; 平野愛弓; 水柿義直
Poster presentation, Japanese, 応用物理学会 第69回応用物理学会春季学術講演会, 応用物理学会, 神奈川県相模原市, Domestic conference
25 Mar. 2022
22 Mar. 2022- 26 Mar. 2022

金コロイド二段階液浸法を用いて作製した単一電子トランジスタの電気的特性
小林海斗; 藤倉健太; 浦江哲也; 守屋雅隆; 島田 宏; 水柿義直
Oral presentation, Japanese, 電子情報通信学会技術研究報告（電子部品・材料研究会）, 電子情報通信学会, オンライン, Domestic conference
01 Mar. 2022
01 Mar. 2022- 01 Mar. 2022

[70]PCBMを混合した自立型脂質二分子膜の電気的特性
嶋田佳宏; 平松大樹; 佐藤 陸; 守屋雅隆; 但木大介; 平野愛弓; 水柿義直
Oral presentation, Japanese, 電子情報通信学会技術研究報告（電子部品・材料研究会）, 電子情報通信学会, オンライン, Domestic conference
01 Mar. 2022
01 Mar. 2022- 01 Mar. 2022

単一磁束量子の2進パルス列を用いたD/A変換器の動作実証
瀬賀直功; 曽明裕太; 島田 宏; 水柿義直
Oral presentation, Japanese, 電子情報通信学会技術研究報告（超伝導エレクトロニクス）, 電子情報通信学会, オンライン, Domestic conference
21 Jan. 2022
21 Jan. 2022- 21 Jan. 2022

Operation of a 4-bit RSFQ digital-to-analog converter based on a binary split-confluence configuration
N. Sega; Y. Somei; H. Shimada; Y. Mizugaki
Oral presentation, English, The 34th International Symposium on Superconductivity (ISS 2021), On-line, Peer-reviewed, International conference
01 Dec. 2021
30 Nov. 2021- 02 Dec. 2021

Operation of Double-Flux-Quantum Amplifiers Fabricated Using a 10 kA/cm2 Nb/AlOx/Nb Integration Process
Y. Mizugaki; Y. Somei; H. Shimada
Oral presentation, English, The 14th Superconducting SFQ VLSI Workshop (SSV 2021) / 3rd Workshop on Quantum and Classical Cryogenic Devices, Circuits, and Systems (QCCC 2021), Yokohama, Japan, International conference
10 Nov. 2021
09 Nov. 2021- 10 Nov. 2021

Electrical Characteristics of Single-Electron Transistors Made by Dielectrophoresis of Gold Nanoparticles with Different Diameters
T. Urae; T. Yagai; K. Sekine; M. Moriya; H. Shimada; A. Hirano-Iwata; F. Hirose; Y. Mizugaki
Poster presentation, English, 34th International Microprocesses and Nanotechnology Conference (MNC 2021), Japan Society of Applied Physics, On-line, Peer-reviewed, International conference
26 Oct. 2021
26 Oct. 2021- 29 Oct. 2021

Superconducting Josephson digital-to-analog converters for quantum voltage generation
Y. Mizugaki
Invited oral presentation, English, International Symposium on Advanced Science and Technology, Invited, College of Science, National Chung Hsing University (NCHU), Taichung, Taiwan, and On-line, International conference
27 Oct. 2021
27 Oct. 2021- 27 Oct. 2021

バイナリ分割合成方式を用いた4-bit RSFQ-DAC の動作実証
瀬賀直功; 曽明裕太; 島田 宏; 水柿義直
Oral presentation, Japanese, 電子情報通信学会ソサイエティ大会, 電子情報通信学会, Domestic conference
16 Sep. 2021
14 Sep. 2021- 17 Sep. 2021

タイミングジッタを利用するRSFQ真性乱数生成器の性能評価
佐藤健太; 瀬賀直功; 曽明裕太; 島田 宏; 小野美 武; 水柿義直
Oral presentation, Japanese, 電子情報通信学会ソサイエティ大会, 電子情報通信学会, Domestic conference
16 Sep. 2021
14 Sep. 2021- 17 Sep. 2021

単一クーパー対トランジスタによるフォノン検出
Jutarat Tanarom; 水柿義直; 島田 宏
Oral presentation, Japanese, 電子情報通信学会技術研究報告（超伝導エレクトロニクス）, 電子情報通信学会, オンライン, Domestic conference
06 Aug. 2021
06 Aug. 2021- 06 Aug. 2021

2種類の粒径の金ナノ粒子を誘電泳動させ作製した単一電子トランジスタの特性
浦江哲也; 谷貝知起; 関根一真; 守屋雅隆; 島田 宏; 平野愛弓; 廣瀬文彦; 水柿義直
Oral presentation, Japanese, 応用物理学会 第68回応用物理学会春季学術講演会, 応用物理学会, オンライン, Domestic conference
19 Mar. 2021
16 Mar. 2021- 19 Mar. 2021

Nb 10 kA/cm2プロセスで作製した磁気結合SFQ伝搬回路の特性評価
曽明裕太; 島田 宏; 水柿義直
Poster presentation, Japanese, 応用物理学会 第68回応用物理学会春季学術講演会, 応用物理学会, オンライン, Domestic conference
16 Mar. 2021
16 Mar. 2021- 19 Mar. 2021

レジスト溝内に配置された金ナノ粒子ランダム配列における粒子間距離
関根一真; 守屋雅隆; 島田 宏; 平野愛弓; 廣瀬文彦; 水柿義直
Poster presentation, Japanese, 応用物理学会 第68回応用物理学会春季学術講演会, 応用物理学会, オンライン, Domestic conference
16 Mar. 2021
16 Mar. 2021- 19 Mar. 2021

オンチップ電磁石を利用して作製したCoナノ粒子配列からなる強磁性単一電子素子
藤倉健太; 浦江哲也; 関根一真; 守屋雅隆; 島田 宏; 平野愛弓; 廣瀬文彦; 水柿義直
Oral presentation, Japanese, 電子情報通信学会技術研究報告（電子部品・材料研究会）, 電子情報通信学会, オンライン, Domestic conference
03 Mar. 2021
03 Mar. 2021- 03 Mar. 2021

CNTを混合した脂質二分子膜越しに流れる電流変動量の印加電圧依存性
平松大樹; 佐藤 陸; 平田はるか; 守屋雅隆; 廣瀬文彦; 平野愛弓; 水柿義直
Oral presentation, Japanese, 電子情報通信学会技術研究報告（電子部品・材料研究会）, 電子情報通信学会, オンライン, Domestic conference
03 Mar. 2021
03 Mar. 2021- 03 Mar. 2021

AC impedance of a free-standing bilayer lipid membrane formed over an aperture in a nanofabricated silicon chip
Y. Tomioka; H. Hirata; S. Takashima; M. Moriya; H. Shimada; F. Hirose; A. Hirano-Iwata; Y. Mizugaki
Oral presentation, English, 11th International Workshop on Nanostructures & Nanoelectronics, RIEC, Tohoku University, on-line, International conference
02 Mar. 2021
01 Mar. 2021- 02 Mar. 2021

Electrical Characteristics of PCBM-embedded Bilayer Lipid Membranes under Light Irradiation
H. Hirata; Y. Tomioka; M. Moriya; H. Shimada; F. Hirose; A. Hirano-Iwata; Y. Mizugaki
Poster presentation, English, The Irago Conference 2020 (Interdisciplinary Research And Global Outlook), Online, Peer-reviewed, http://iragoconference.jp/, International conference
11 Dec. 2020
11 Dec. 2020- 11 Dec. 2020

Enhanced Operation Frequencies of Superconducting Voltage Multiplier with Quantum Accuracy
Y. Somei; H. Shimada; Y. Mizugaki
Poster presentation, English, The Irago Conference 2020 (Interdisciplinary Research And Global Outlook), Online, Peer-reviewed, http://iragoconference.jp/, International conference
11 Dec. 2020
11 Dec. 2020- 11 Dec. 2020

Nb 10-kA/cm2集積プロセスにより作製した両極性DFQアンプの最大動作周波数向上
曽明裕太; 島田 宏; 水柿義直
Oral presentation, Japanese, 電子情報通信学会技術研究報告（超伝導エレクトロニクス）, 電子情報通信学会, オンライン, Domestic conference
25 Nov. 2020
25 Nov. 2020- 26 Nov. 2020

PCBM-embedded bilayer lipid membranes electrically evaluated using sequential measurements of photo-induced current and electrochemical impedance spectroscopy
H. Hirata; Y. Tomioka; M. Moriya; H. Shimada; F. Hirose; A. Hirano-Iwata; Y. Mizugaki
Oral presentation, English, 33rd International Microprocesses and Nanotechnology Conference (MNC 2020), Japan Society of Applied Physics, Online, Peer-reviewed, International conference
09 Nov. 2020
09 Nov. 2020- 12 Nov. 2020

10 kA/cm2プロセスを用いたDouble-SQUID分布型RSFQアンプの動作検証
瀬賀直功; 山崎洸生; 曽明裕太; 島田 宏; 水柿義直
Oral presentation, Japanese, 電子情報通信学会ソサイエティ大会, 電子情報通信学会, Domestic conference
17 Sep. 2020
15 Sep. 2020- 18 Sep. 2020

原子層堆積法を援用した斜め蒸着法による単一電子素子の作製
小池威廣; 今野寛己; 水柿義直; 島田 宏; 三浦正範; 鹿又健作; 廣瀬文彦
Oral presentation, Japanese, 第81回応用物理学会秋季学術講演会, 応用物理学会, Domestic conference
09 Sep. 2020
08 Sep. 2020- 11 Sep. 2020

トグル・ストレージ・ループを有する単一磁束量子NOTゲートのバイアスマージン改善と多入力否定論理ゲートへの拡張
山崎洸生; 島田 宏; 水柿義直
Oral presentation, Japanese, 第81回応用物理学会秋季学術講演会, 応用物理学会, Domestic conference
08 Sep. 2020
08 Sep. 2020- 11 Sep. 2020

フォノン照射による微小Josephson接合列の特性変化
渡邉拓磨; 水柿義直; 島田 宏
Oral presentation, Japanese, 日本物理学会 第75回年次大会, 日本物理学会, 名古屋市千種区, Domestic conference
16 Mar. 2020
16 Mar. 2020- 19 Mar. 2020

10-kA/cm2 Nb集積プロセスを用いたDouble-Flux-Quantum Amplifierの再設計と動作検証
曽明裕太; 山崎洸生; 島田 宏; 水柿義直
Poster presentation, Japanese, 応用物理学会 第67回応用物理学会春季学術講演会, 応用物理学会, 東京都千代田区, Domestic conference
12 Mar. 2020
12 Mar. 2020- 15 Mar. 2020

外部磁場印加下での誘電泳動で作製した磁性ナノ粒子配列における単一電子帯電効果
谷貝知起; 森林 誠; 守屋雅隆; 島田 宏; 平野愛弓; 廣瀬文彦; 水柿義直
Oral presentation, Japanese, 応用物理学会 第67回応用物理学会春季学術講演会, 応用物理学会, 東京都千代田区, Domestic conference
12 Mar. 2020
12 Mar. 2020- 15 Mar. 2020

AC impedance of a free-standing bilayer lipid membrane formed over an aperture in a nanofabricated silicon chip
Y. Tomioka; S. Takashima; M. Moriya; H. Shimada; F. Hirose; A. Hirano-Iwata; Y. Mizugaki
Oral presentation, English, 11th International Workshop on Nanostructures & Nanoelectronics, RIEC, Tohoku University, Sendai, Japan, International conference
06 Mar. 2020
05 Mar. 2020- 06 Mar. 2020

単分子膜貼り合わせ法で作製したグラフェン混合脂質二分子膜の光応答特性
佐藤 陸; 平田はるか; 冨岡康貴; 守屋雅隆; 廣瀬文彦; 平野愛弓; 水柿義直
Oral presentation, Japanese, 電子情報通信学会技術研究報告（電子部品・材料研究会）, 電子情報通信学会, 東京都八王子市, Domestic conference
29 Feb. 2020
28 Feb. 2020- 29 Feb. 2020

誘電泳動法で作製した2種類の粒径の金ナノ粒子列からなる単一電子素子
浦江哲也; 関根一真; 谷貝知起; 守屋雅隆; 島田 宏; 平野愛弓; 廣瀬文彦; 水柿義直
Oral presentation, Japanese, 電子情報通信学会技術研究報告（電子部品・材料研究会）, 電子情報通信学会, 東京都八王子市, Domestic conference
29 Feb. 2020
28 Feb. 2020- 29 Feb. 2020

Design and operation of single-flux-quantum logic gates with a floating storage loop
K. Yamazaki; H. Shimada; Y. Mizugaki
Poster presentation, English, The 13th Superconducting SFQ VLSI Workshop (SSV 2020) & IEICE Technical Committee on Superconductive Electronics (SCE), Yokohama, Japan, International conference
17 Jan. 2020
16 Jan. 2020- 17 Jan. 2020

Improved Maximum Output Voltage of Double-Flux-Quantum Amplifier Fabricated Using 10-kA/cm2 Nb integration process
Y. Somei; K. Yamazaki; H. Shimada; Y. Mizugaki
Poster presentation, English, The 13th Superconducting SFQ VLSI Workshop (SSV 2020) & IEICE Technical Committee on Superconductive Electronics (SCE), Yokohama, Japan, International conference
17 Jan. 2020
16 Jan. 2020- 17 Jan. 2020

Design and Error-Rate Evaluation of RSFQ Logic Gates Comprising a Toggle Storage Loop
K. Yamazaki; H. Shimada; Y. Mizugaki
Poster presentation, English, The 32nd International Symposium on Superconductivity (ISS 2019), Kyoto, Japan, Peer-reviewed, International conference
05 Dec. 2019
03 Dec. 2019- 05 Dec. 2019

Enhanced voltage swing of RSFQ output amplifiers equipped with double-stack SQUIDs
Y. Mizugaki; K. Higuchi; H. Shimada
Poster presentation, English, The 32nd International Symposium on Superconductivity (ISS 2019), Kyoto, Japan, Peer-reviewed, International conference
04 Dec. 2019
03 Dec. 2019- 05 Dec. 2019

Applicability of Small Josephson Junction Arrays as Radiation Detectors
T. Suzuki; G.M. Kanyolo; H. Nishigaki; Y. Mizugaki; H. Shimada
Poster presentation, English, International Workshop on Hybrid Quantum Systems (HQS2019), Matsue, Shimane, Japan, International conference
04 Dec. 2019
01 Dec. 2019- 04 Dec. 2019

Long Range Current Correlation for Adjacent Small Josephson Junction Devices
T. Watanabe; Y. Mizugaki; H. Shimada
Poster presentation, English, The International School and Symposium on Nanoscale Transport and phoTonics (ISNTT 2019), NTT, Atsugi, Kanagawa, Japan, International conference
20 Nov. 2019
19 Nov. 2019- 22 Nov. 2019

Capacitance extraction method of a free-standing bilayer lipid membrane formed over an aperture in a nanofabricated silicon chip
Y. Tomioka; S. Takashima; M. Moriya; H. Shimada; F. Hirose; A. Hirano-Iwata; Y. Mizugaki
Oral presentation, English, 32nd International Microprocesses and Nanotechnology Conference (MNC 2019), Hiroshima, Japan, Peer-reviewed, International conference
31 Oct. 2019
28 Oct. 2019- 31 Oct. 2019

Single-Electron Transistor Made of Arrays of Carbon-Coated Cobalt Nanoparticles Assembled by Dielectrophoresis
T. Yagai; M. Moribayashi; M. Moriya; H. Shimada; A. Hirano-Iwata; F. Hirose; Y. Mizugaki
Poster presentation, English, 32nd International Microprocesses and Nanotechnology Conference (MNC 2019), Hiroshima, Japan, Peer-reviewed, International conference
30 Oct. 2019
28 Oct. 2019- 31 Oct. 2019

Non-linear responses in AC characteristics of bilayer lipid membrane
Y. Tomioka; S. Takashima; M. Moriya; H. Shimada; A. Hirano-Iwata; F. Hirose; Y. Mizugaki
Poster presentation, English, The Irago Conference 2019 (Interdisciplinary Research And Global Outlook), Chofu, Tokyo, Japan, International conference
29 Oct. 2019

炭素被覆コバルトナノ粒子配列における単一電子帯電効果
谷貝知起; 森林誠; 守屋雅隆; 島田宏; 平野愛弓; 廣瀬文彦; 水柿義直
Oral presentation, Japanese, 第80回応用物理学会秋季学術講演会, 応用物理学会, 北海道札幌市, Domestic conference
20 Sep. 2019

回路面積を減じた単一磁束量子NOTゲートの設計及びエラーレートの評価
山崎洸生; 島田宏; 水柿義直
Oral presentation, Japanese, 第80回応用物理学会秋季学術講演会, 応用物理学会, 北海道札幌市, Domestic conference
20 Sep. 2019

磁気結合入力を用いた並列入力型DFQ アンプ
曽明裕太; 山崎洸生; 樋口孔明; 島田宏; 水柿義直
Oral presentation, Japanese, 第80回応用物理学会秋季学術講演会, 応用物理学会, 北海道札幌市, Domestic conference
20 Sep. 2019

シリコン微細加工チップに形成された自立型脂質二分子膜の容量抽出法
冨岡康貴; 高島匠吾; 守屋雅隆; 島田宏; 廣瀬文彦; 平野愛弓; 水柿義直
Oral presentation, Japanese, 第80回応用物理学会秋季学術講演会, 応用物理学会, 北海道札幌市, Domestic conference
19 Sep. 2019

微小Josephson接合列の輻射検出器としての利用性の評価
鈴木俊貴; Kanyolo Godwill Mbiti; 西垣宏志; 水柿義直; 島田宏
Oral presentation, Japanese, 第80回応用物理学会秋季学術講演会, 応用物理学会, 北海道札幌市, Domestic conference
19 Sep. 2019

Double-stack SQUIDを採用した12段RSFQ分布型出力アンプの試作と動作検証
樋口孔明; 島田 宏; 水柿義直
Oral presentation, Japanese, 2019年電子情報通信学会ソサイエティ大会, 電子情報通信学会, 大阪府豊中市, Domestic conference
13 Sep. 2019

SFQパルス発振器に基づくSFQ 乱数生成器の試作
小野美 武; 水柿義直
Oral presentation, Japanese, 2019年電子情報通信学会ソサイエティ大会, 電子情報通信学会, 大阪府豊中市, Domestic conference
13 Sep. 2019

二重SQUIDを採用したRSFQ分布型出力アンプの設計と動作実証
樋口孔明; 島田 宏; 水柿義直
Oral presentation, Japanese, 電子情報通信学会 超伝導エレクトロニクス研究会, 電子情報通信学会, 東京, Domestic conference
09 Aug. 2019

微小Josephson接合列の輻射検出器としての利用性の評価
鈴木俊貴; カニョロ ゴドゥウィリ ビティ; 西垣宏志; 水柿義直; 島田 宏
Oral presentation, Japanese, 電子情報通信学会 超伝導エレクトロニクス研究会, 電子情報通信学会, 東京, Domestic conference
09 Aug. 2019

カーボンナノチューブを混合した自立型平面脂質二分子膜の交流インピーダンスの経時変化
高島匠吾; 守屋雅隆; 冨岡康貴; 平田はるか; 廣瀬文彦; 平野愛弓; 水柿義直
Oral presentation, Japanese, 電子情報通信学会 電子デバイス研究会, 電子情報通信学会, 仙台市, Domestic conference
18 Apr. 2019

強く容量結合した短い微小ジョセフソン接合列における電流誘引現象
村井飛天; 水柿義直; 島田 宏
Oral presentation, Japanese, 日本物理学会 第74回年次大会, 日本物理学会, 福岡県福岡市, Domestic conference
17 Mar. 2019

単一電子素子応用を目指した誘電泳動による金ナノ粒子整列の統計調査
森林誠; 谷貝知起; 守屋雅隆; 島田 宏; 平野愛弓; 廣瀬文彦; 水柿義直
Poster presentation, Japanese, 応用物理学会 第66回応用物理学会春季学術講演会, 応用物理学会, 東京都目黒区, Domestic conference
11 Mar. 2019

等価回路解析による脂質二分子膜の薄膜化の評価
冨岡康貴; 高島匠吾; 守屋雅隆; 島田 宏; 廣瀬文彦; 平野愛弓; 水柿義直
Poster presentation, Japanese, 応用物理学会 第66回応用物理学会春季学術講演会, 応用物理学会, 東京都目黒区, Domestic conference
10 Mar. 2019

Single-electron devices fabricated using percolative connections of gold nanoparticles
Y. Mizugaki; M. Moriya; H. Shimada; K. Matsumoto; M. Moribayashi; T. Yagai; A. Hirano-Iwata; F. Hirose
Oral presentation, English, 10th International Workshop on Nanostructures & Nanoelectronics, RIEC, Tohoku University, Sendai, Japan, International conference
07 Mar. 2019

粒径の異なる2種類の金ナノ粒子から成るランダム配列の電気的特性
関根一真; 森林 誠; 守屋雅隆; 谷貝知起; 島田 宏; 平野愛弓; 廣瀬文彦; 水柿義直
Oral presentation, Japanese, 電子情報通信学会技術研究報告（電子部品・材料研究会）, 電子情報通信学会, 東京都調布市, Domestic conference
01 Mar. 2019

P3HTを混合した自立型脂質二分子膜の光応答特性
平田はるか; 冨岡康貴; 高島匠吾; 守屋雅隆; 廣瀬文彦; 平野愛弓; 水柿義直
Oral presentation, Japanese, 電子情報通信学会技術研究報告（電子部品・材料研究会）, 電子情報通信学会, 東京都調布市, Domestic conference
01 Mar. 2019

Design and Operation of a Distributed Amplifier Comprising Double-SQUID Elements
K. Higuchi; H. Shimada; Y. Mizugaki
Oral presentation, English, The 12th Superconducting SFQ VLSI Workshop (SSV 2019), Kobe, Japan, International conference
17 Jan. 2019

Series-Connected Double-Flux-Quantum Amplifiers
Y. Somei; K. Yamazaki; K. Higuchi; H. Shimada; Y. Mizugaki
Poster presentation, English, The 12th Superconducting SFQ VLSI Workshop (SSV 2019), Kobe, Japan, International conference
16 Jan. 2019

Design and Test of a CONNECT-Library-Compatible XNOR Cell Implemented with a Compact NOT Element
K. Yamazaki; K. Higuchi; H. Shimada; Y. Mizugaki
Poster presentation, English, The 12th Superconducting SFQ VLSI Workshop (SSV 2019), Kobe, Japan, International conference
16 Jan. 2019

Design and Operation of Distributed Double-SQUID Amplifier for RSFQ Circuits
K. Higuchi; H. Shimada; Y. Mizugaki
Poster presentation, English, The 31st International Symposium on Superconductivity (ISS 2018), AIST, Tsukuba, Japan, International conference
Dec. 2018

Evaluation of Inter-Particle Distance of Gold Nanoparticles Dispersed on Silane-Treated Substrates for Fabrication of Dithiol-Connected Arrays
T. Yagai; K. Matsumoto; M. Moriyabashi; M. Moriya; H. Shimada; A. Hirano-Iwata; F. Hirose; Y. Mizugaki
Poster presentation, English, 31st International Microprocesses and Nanotechnology Conference (MNC 2018), Sapporo, Japan, International conference
16 Nov. 2018

Equivalent circuit model modified for free-standing bilayer lipid membranes beyond 1 TΩ
Y. Tomioka; S. Takashima; M. Moriya; H. Shimada; F. Hirose; A. Hirano-Iwata; Y. Mizugaki
Poster presentation, English, 31st International Microprocesses and Nanotechnology Conference (MNC 2018), Sapporo, Japan, International conference
16 Nov. 2018

Correlation of currents in remote arrays of small Josephson junctions through the quasiparticle excitation
T. Watanabe; Y. Mizugaki; H. Shimada
Poster presentation, English, International Symposium on Frontiers of Quantum Transport in Nano Science (QTNS2018), International conference
08 Nov. 2018

Single-electron charging effects observed in arrays of gold nanoparticles formed by dielectrophoresis between SAM-coated electrodes
M. Moribayashi; T. Yagai; M. Moriya; H. Shimada; A. Hirano-Iwata; F. Hirose; Y. Mizugaki
Poster presentation, English, The Irago Conference 2018 (Interdisciplinary Research And Global Outlook), International conference
01 Nov. 2018

Temporal change of AC impedance measured across a free-standing bilayer lipid membrane
S. Takashima; M. Moriya; Y. Kimura; A. Hirano-Iwata; Y. Mizugaki
Poster presentation, English, The Irago Conference 2018 (Interdisciplinary Research And Global Outlook), International conference
01 Nov. 2018

1000-fold double-flux-quantum voltage multiplier employing directional propagation of flux quanta through asymmetrically-damped junction branches
Y. Mizugaki; Y. Arai; T. Watanabe; H. Shimada
Oral presentation, English, 2018 Applied Superconductivity Conference (ASC2018), Seattle, Washington, USA, International conference
29 Oct. 2018

レジスト溝内での金ナノ粒子パーコレーション接続を利用した単一電子素子作製方法
松本和彦; 守屋雅隆; 森林 誠; 谷貝知起; 島田 宏; 廣瀬文彦; 平野愛弓; 水柿義直
Oral presentation, Japanese, 第79回応用物理学会秋季学術講演会, 応用物理学会, 愛知県名古屋市, Domestic conference
21 Sep. 2018

カーボンナノチューブを混合した自立型平面脂質二分子膜で観測された交流インピーダンスの繰り返し増減
高島匠吾; 冨岡康貴; 守屋雅隆; 島田 宏; 廣瀬文彦; 平野愛弓; 水柿義直
Poster presentation, Japanese, 第79回応用物理学会秋季学術講演会, 応用物理学会, 愛知県名古屋市, Domestic conference
20 Sep. 2018

脂質二分子膜の交流特性測定時に見られた非線形応答
冨岡康貴; 高島匠吾; 守屋雅隆; 島田 宏; 廣瀬文彦; 平野愛弓; 水柿義直
Poster presentation, Japanese, 第79回応用物理学会秋季学術講演会, 応用物理学会, 愛知県名古屋市, Domestic conference
20 Sep. 2018

二重SQUID構造RSFQ分布型アンプの特性評価
樋口孔明; 島田 宏; 水柿義直
Oral presentation, Japanese, 2018年電子情報通信学会ソサイエティ大会, 電子情報通信学会, 石川県金沢市, Domestic conference
14 Sep. 2018

非対称なダンピング係数によるSFQ伝搬方向制御を利用した1000倍DFQアンプの設計・試作・動作検証
荒井祐真; 渡邉智希; 島田 宏; 水柿義直
Oral presentation, Japanese, 2018年電子情報通信学会ソサイエティ大会, 電子情報通信学会, 石川県金沢市, Domestic conference
14 Sep. 2018

微小ジョセフソン接合列の電流が引き起こす近接素子中の準粒子励起
渡邉拓磨; 水柿義直; 島田 宏
Oral presentation, Japanese, 日本物理学会 2018年秋季大会, 日本物理学会, Domestic conference
10 Sep. 2018

金ナノ粒子ランダム配列において観測された単一電子トランジスタ的な特性
守屋雅隆; Tran Thi Thu Huong; 松本和彦; 森林 誠; 島田 宏; 木村康男; 平野愛弓; 水柿義直
Oral presentation, Japanese, 電子情報通信学会 電子デバイス研究会, 電子情報通信学会, 米沢, Domestic conference
19 Apr. 2018

シラン化処理を施した基板上に作製した金ナノ粒子配列の単一電子素子への応用
谷貝知起; 松本和彦; 森林 誠; 守屋雅隆; 島田 宏; 平野愛弓; 廣瀬文彦; 水柿義直
Oral presentation, Japanese, 電子情報通信学会 電子部品・材料研究会, 電子情報通信学会, 東京, Domestic conference
02 Mar. 2018

自立型脂質二分子膜の等価回路解析
冨岡康貴; 高島匠吾; 守屋雅隆; 廣瀬文彦; 平野愛弓; 水柿義直
Oral presentation, Japanese, 電子情報通信学会 電子部品・材料研究会, 電子情報通信学会, 東京, Domestic conference
02 Mar. 2018

Numerical Simulation for Single-Electron Charging Effects in Random Arrays of Small Tunnel Junctions
Y. Mizugaki; M. Moriya; H. Shimada; K. Matsumoto; M. Moribayashi; T. Yagai; Y. Kimura; A. Hirano-Iwata; F. Hirose
Oral presentation, English, 9th International Workshop on Nanostructures & Nanoelectronics, RIEC, Tohoku University, Sendai, Japan, International conference
02 Mar. 2018

金ナノ粒子ランダムアレイの抵抗結合型単一電子トランジスタ的特性
守屋雅隆; Tran Thi Thu Huong; 松本和彦; 森林 誠; 島田 宏; 木村康男; 平野愛弓; 水柿義直
Oral presentation, Japanese, 応用物理学会 第65回応用物理学会春季学術講演会, 応用物理学会, 東京都新宿区, Domestic conference
Mar. 2018

誘電泳動を用いて作製した金ナノ粒子配列における単一電子帯電効果
森林誠; 松本和彦; 谷貝知起; 守屋雅隆; 島田 宏; 平野愛弓; 廣瀬文彦; 水柿義直
Poster presentation, Japanese, 応用物理学会 第65回応用物理学会春季学術講演会, 応用物理学会, 東京都新宿区, Domestic conference
Mar. 2018

RSFQ回路用分布型アンプのバイアス電流-出力電圧特性
樋口孔明; 島田 宏; 水柿義直
Oral presentation, Japanese, 2018年電子情報通信学会総合大会, Domestic conference
Mar. 2018

室温ALD法を援用した斜め蒸着法による微小トンネル接合の作製
吉川圭祐; 伊藤直輝; 今野寛己; 水柿義直; 島田 宏; 鹿又健作; 廣瀬文彦
Oral presentation, Japanese, 応用物理学会 第65回応用物理学会春季学術講演会, 応用物理学会, 東京都新宿区, Domestic conference
Mar. 2018

レジスト溝内に選択配置して作製した金ナノ粒子配列での単一電子帯電効果
松本和彦; 森林 誠; 谷貝知起; 守屋雅隆; 島田 宏; 木村康男; 平野愛弓; 廣瀬文彦; 水柿義直
Oral presentation, Japanese, 電子情報通信学会,電子デバイス研究会&シリコン材料・デバイス研究会, 電子情報通信学会, 札幌市, Domestic conference
28 Feb. 2018

微小トンネル接合ランダム配列での単一電子帯電効果に関する数値シミュレーション
水柿義直; 守屋雅隆; 島田 宏; 松本和彦; 森林 誠; 谷貝知起; 木村康男; 平野愛弓; 廣瀬文彦
Oral presentation, Japanese, 電子情報通信学会,電子デバイス研究会&シリコン材料・デバイス研究会, 電子情報通信学会, 札幌市, Domestic conference
28 Feb. 2018

Double-Flux-Quantum Amplifier Designed with Adjusted Damping Parameters for Proper Propagation of SFQ Pulses
Y. Mizugaki; Y. Arai; T. Watanabe
Oral presentation, English, The 11th Superconducting SFQ VLSI Workshop (SSV 2018) / 6th CRAVITY Symposium, Tsukuba, Japan, International conference
08 Feb. 2018

Double-Flux-Quantum Amplifier with a Single-Flux-Biasing Line
Y. Arai; T. Watanabe; K. Higuchi; H. Shimada; Y. Mizugaki
Poster presentation, English, 30th International Symposium on Superconductivity (ISS 2017), Chiyoda, Tokyo, International conference
15 Dec. 2017

磁束バイアス線を1本に減じたDFQアンプの設計と動作検証
荒井祐真; 渡邉智希; 樋口孔明; 島田 宏; 水柿義直
Poster presentation, Japanese, 電気学会研究会 金属・セラミックス／超電導機器合同研究会, 電気学会, つくば市, Domestic conference
11 Dec. 2017

Dependence of threshold voltages on temperature observed in random arrays of Au nanoparticles
M. Moriya; M. Moribayashi; K. Matsumoto; H. T. T. Tran; H. Shimada; Y. Kimura; A. Hirano-Iwata; Y. Mizugaki
Poster presentation, English, International Symposium on Nanoscale Transport and Technology (ISNTT2017), Atsugi, Kanagawa, International conference
15 Nov. 2017

Excitons in Capacitively Coupled Chains of Small Josephson Junctions
H. Shimada; K. Matsudo; C. Ishida; H. Murai; Y. Mizugaki
Poster presentation, English, International Symposium on Nanoscale Transport and Technology (ISNTT2017), NTT, Atsugi, Kanagawa, Japan, International conference
14 Nov. 2017

Dependence of Threshold Voltages on Temperature observed in an Array of Au Nanoparticles
M. Moriya; M. Moribayashi; K. Matsumoto; H. T. T. Tran; H. Shimada; Y. Kimura; A. Hirano-Iwata; Y. Mizugaki
Poster presentation, English, International Symposium on Novel Energy Nanomaterials, Catalysts and Surfaces for Future Earth, Chofu, Tokyo, International conference
28 Oct. 2017

SFQパルス周波数変調型D/A変換器の両極性出力化
渡邉智希; 島田 宏; 水柿義直
Oral presentation, Japanese, 電子情報通信学会ソサイエティ大会, 電子情報通信学会, 東京都世田谷区, Domestic conference
13 Sep. 2017

局所陽極酸化によるアルミニウムナノワイヤの形成
福元隆弘; 守屋雅隆; 水柿義直; 但木大介; Ma Teng; 平野愛弓; 庭野道夫; 木村 康男
Poster presentation, Japanese, 第78回応用物理学会秋季学術講演会, 応用物理学会, 福岡県福岡市, Domestic conference
07 Sep. 2017

シャント抵抗制御型DFQアンプの再設計と動作検証
荒井祐真; 樋口孔明; 島田 宏; 水柿義直
Oral presentation, Japanese, 第78回応用物理学会秋季学術講演会, 応用物理学会, 福岡県福岡市, Domestic conference
07 Sep. 2017

単分子貼り合わせ法を用いた脂質二分子膜形成時に見られる静電容量値の変化と膜寿命との相関関係
高島匠吾; 守屋雅隆; 木村康男; 平野愛弓; 水柿義直
Oral presentation, Japanese, 第78回応用物理学会秋季学術講演会, 応用物理学会, 福岡県福岡市, Domestic conference
07 Sep. 2017

金ナノ粒子ランダム配列において室温で観測された負性微分抵抗のゲート電圧変調
守屋雅隆; Tran Thi Thu Huong; 森林 誠; 松本和彦; 島田 宏; 木村康男; 平野愛弓; 水柿義直
Oral presentation, Japanese, 第78回応用物理学会秋季学術講演会, 応用物理学会, 福岡県福岡市, Domestic conference
07 Sep. 2017

Magnetoresistance of single-electron transistors comprising a superconducting island with ferromagnetic leads
Y. Mizugaki; M. Takiguchi; N. Tamura; H. Shimada
Poster presentation, English, 28th International Conference on Low Temperature Physics (LT28), Chalmers University of Technology, the Nobelinstitute for Physics, the International Union of Pure and Applied Research IUPAP, Gothenburg, Sweden, International conference
10 Aug. 2017

The radio-frequency response of linear arrays of mesoscopic Josephson junctions and its detector application
G. M. Kanyolo; H. Nishigaki; Y. Mizugaki; H. Shimada
Poster presentation, English, 28th International Conference on Low Temperature Physics (LT28), Chalmers University of Technology, the Nobelinstitute for Physics, the International Union of Pure and Applied Research IUPAP, Gothenburg, Sweden, International conference
10 Aug. 2017

Cooper-pair excitons and quasiparticle excitons in capacitively coupled chains of small Josephson junctions
H. Shimada; K. Matsudo; C. Ishida; Y. Mizugaki
Poster presentation, English, 28th International Conference on Low Temperature Physics (LT28), Chalmers University of Technology, the Nobelinstitute for Physics, the International Union of Pure and Applied Research IUPAP, Gothenburg, Sweden, International conference
10 Aug. 2017

3電極間に滴下法で作製した金ナノ粒子ランダム配列における単一電子帯電効果
森林誠; 松本和彦; Tran Thi Thu Huong; 守屋雅隆; 島田 宏; 木村康男; 平野愛弓; 水柿義直
Oral presentation, Japanese, 第94回 低温工学・超電導学会研究発表会, 低温工学・超電導学会, タワーホール船堀, 江戸川区, 東京, Domestic conference
23 May 2017

DFQアンプの誤動作時における磁束量子ダイナミクス
樋口孔明; 荒井祐真; 水柿義直
Oral presentation, Japanese, 第94回 低温工学・超電導学会研究発表会, 低温工学・超電導学会, タワーホール船堀, 江戸川区, 東京, Domestic conference
23 May 2017

強磁性体−超伝導体−強磁性体電極で構成される単一電子トランジスタのゲート電圧と外部磁場に対する応答
水柿義直; 滝口将志; 田村伸行; 島田 宏
Oral presentation, Japanese, 電子情報通信学会,電子デバイス研究会, 電子情報通信学会, 宮城県仙台市, Domestic conference
21 Apr. 2017

容量結合した微小Josephson接合列におけるトンネル伝導(2)
松戸広太; 村井飛天; 水柿義直; 島田宏
Oral presentation, Japanese, 日本物理学会 第72回年次大会, 日本物理学会, 大阪府豊中市, Domestic conference
17 Mar. 2017

Numerical Study on Stochastic Resonance in a Single-Electron Hysteretic Inverter
Y. Mizugaki; Tran T. T. Huong
Oral presentation, English, 8th International Workshop on Nanostructures & Nanoelectronics, RIEC, Tohoku University, Sendai, Japan, International conference
06 Mar. 2017

Design and Operation of Single-Flux-Quantum Bipolar Digital-to-Analog Converters
Y. Mizugaki; T. Watanabe
Oral presentation, English, Superconducting SFQ VLSI Workshop (SSV 2017), Nagoya, Japan, International conference
21 Feb. 2017

Thermally-Fluctuated Single-Flux-Quantum Pulse Intervals Reflected in Input-Output Characteristics of a Double-Flux-Quantum Amplifier
Y. Mizugaki; Y. Urai; H. Shimada
Oral presentation, English, 29th International Symposium on Superconductivity (ISS 2016), Chiyoda, Tokyo, Japan, International conference
14 Dec. 2016

Fabrication of a single-electron device by successive dispersion of two different-sized nanoparticles
M. Moriya; K. Matsumoto; H. Shimada; Y. Kimura; A. Hirano-Iwata; Y. Mizugaki
Poster presentation, English, The Irago Conference 2016 (Interdisciplinary Research And Global Outlook), International conference
01 Nov. 2016

SFQ-D/A変換器で用いるSFQパルス繰り返し周波数の向上
荒井祐真; 渡邉智希; 澤田和直; 島田 宏; 水柿義直
Oral presentation, Japanese, 第77回応用物理学会秋季学術講演会, 応用物理学会, 新潟市, Domestic conference
15 Sep. 2016

３電極間に滴下法で作製した金ナノ粒子膜における単一帯電効果
松本和彦; Tran Huong; 守屋雅隆; 島田 宏; 木村康男; 平野愛弓; 水柿義直
Oral presentation, Japanese, 第77回応用物理学会秋季学術講演会, 応用物理学会, 新潟市, Domestic conference
13 Sep. 2016

1次元微小Josephson接合列の高周波印加に伴う直流特性変化
Godwill Mbiti Kanyolo; 水柿義直; 島田 宏
Oral presentation, Japanese, 日本物理学会 2016年秋季大会, 日本物理学会, 金沢, Domestic conference
13 Sep. 2016

微小Josephson接合列による超伝導単一電子トランジスタからの輻射検出
西垣宏志; Godwill Mbiti Kanyolo; 水柿義直; 島田 宏
Oral presentation, Japanese, 日本物理学会 2016年秋季大会, 日本物理学会, 金沢, Domestic conference
13 Sep. 2016

容量結合した微小ジョセフソン接合列におけるトンネル伝導
松戸広太; 西垣宏志; 水柿義直; 島田 宏
Oral presentation, Japanese, 日本物理学会 2016年秋季大会, 日本物理学会, 金沢, Domestic conference
13 Sep. 2016

Single-Flux-Quantum Bipolar Digital-to-Analog Converter Comprising Polarity-Switchable Double-Flux-Quantum Amplifier
Y. Mizugaki; T. Watanabe; H. Shimada
Oral presentation, English, 2016 Applied Superconductivity Conference (ASC2016), Denver, CO, USA, International conference
05 Sep. 2016

Thermally-Fluctuated SFQ Pulse Intervals Observed in IO Characteristics of a Double-Flux-Quantum Amplifier
Y. Mizugaki; Y. Urai; H. Shimada
Oral presentation, English, Superconducting SFQ VLSI Workshop (SSV 2016), Yokohama, Japan, International conference
03 Aug. 2016

それぞれ粒径の異なるナノ粒子を散布して作製した2種類の単一電子素子
守屋雅隆; Tran Thi Thu Huong; 松本和彦; 島田 宏; 木村康男; 平野愛弓; 水柿義直
Oral presentation, Japanese, 電子情報通信学会,電子デバイス研究会, 電子情報通信学会, 山形県米沢市, Domestic conference
21 Apr. 2016

微小Alトンネル接合列内での接合特性の均一性向上を目指したSiO援用Dolan法の提案と評価
徳山貴斗; 島田 宏; 水柿義直
Oral presentation, Japanese, 電子情報通信学会,超伝導エレクトロニクス研究会, 電子情報通信学会, 東京都港区, Domestic conference
20 Apr. 2016

繰り返し金ナノ粒子を散布することで作製した単一電子素子
守屋雅隆; Tran Thi Thu Huong; 松本和彦; 島田 宏; 木村康男; 平野愛弓; 水柿義直
Oral presentation, Japanese, 応用物理学会 第63回応用物理学会春季学術講演会, 応用物理学会, 東京都目黒区, Domestic conference
21 Mar. 2016

磁束バイアス線を廃止した±20倍DFQアンプの試作と動作検証
渡邉智希; 水柿義直
Oral presentation, Japanese, 2016年電子情報通信学会総合大会, Domestic conference
15 Mar. 2016

Characteristics of single electron device fabricated by repeated dispersion of gold nano particles
M. Moriya; Tran T. T. Huong; K. Matsumoto; H. Shimada; Y. Kimura; A. Hirano-Iwata; Y. Mizugaki
Oral presentation, English, The Joint Symposium of 10th International Symposium on Medical, Bio- and Nano-Electronics, and 7th International Workshop on Nanostructures & Nanoelectronics, Research Institute of Electrical Communication, Tohoku University, Sendai, Japan, International conference
01 Mar. 2016

両極性出力型DFQアンプの提案と動作実証
渡邉智希; 島田 宏; 水柿義直
Oral presentation, Japanese, 電子情報通信学会,超伝導エレクトロニクス研究会, 電子情報通信学会, 東京都港区, Domestic conference
21 Jan. 2016

SFQマスクROM用各種メモリセルの設計と動作検証
澤田和直; 渡邉智希; 島田 宏; 水柿義直
Oral presentation, Japanese, 電子情報通信学会,超伝導エレクトロニクス研究会, 電子情報通信学会, 東京都港区, Domestic conference
21 Jan. 2016

Design of single-electron hysteretic inverter
Tran T. T. Huong; Y. Mizugaki
Poster presentation, English, International Symposium on Nanoscale Transport and Technology (ISNTT2015), Atsugi, Kanagawa, International conference
17 Nov. 2015

3並列出力型4ビットM系列生成SFQ回路の試作と動作検証
武藤泰明; 浦井芳彰; 澤田和直; 渡邉智希; 水柿義直
Oral presentation, Japanese, 電子情報通信学会ソサイエティ大会, 電子情報通信学会, 仙台市, Domestic conference
10 Sep. 2015

DFQアンプの性能評価におけるSFQパルス列の入力方法
浦井芳彰; 島田 宏; 水柿義直
Oral presentation, Japanese, 電子情報通信学会,超伝導エレクトロニクス研究会, 電子情報通信学会, 横浜市, Domestic conference
04 Aug. 2015

微小Alトンネル接合列内での接合特性の均一性向上を目指したSiO援用Dolan法の提案と評価
徳山貴斗; 島田 宏; 水柿義直
Oral presentation, Japanese, 電子情報通信学会,電子デバイス研究会, 電子情報通信学会, 仙台市, Domestic conference
17 Apr. 2015

微小Josephson接合列におけるBloch振動と電流プラトーの観測
島田 宏; 鹿取俊介; 出口智明; 水柿義直
Oral presentation, Japanese, 日本物理学会 第70回年次大会, 日本物理学会, 東京都新宿区, Domestic conference
21 Mar. 2015

二重微小Josephson接合における接合間のトンネル過程の相互作用
松原明志; 水柿義直; 島田 宏
Oral presentation, Japanese, 日本物理学会 第70回年次大会, 日本物理学会, 東京都新宿区, Domestic conference
21 Mar. 2015

Stochastic Resonance in Single-Electron Inverter Improved by Attachment of Input Discretizer
Tran Thi Thu Huong; H. Shimada; Y. Mizugaki
Oral presentation, English, 応用物理学会 第62回応用物理学会春季学術講演会, 応用物理学会, 神奈川県平塚市, Domestic conference
14 Mar. 2015

非局所測定法を用いた超伝導Al のスピン拡散長評価
佐藤孝幸; 滝口将志; 島田 宏; 水柿義直
Oral presentation, Japanese, 応用物理学会 第62回応用物理学会春季学術講演会, 応用物理学会, 神奈川県平塚市, Domestic conference
13 Mar. 2015

溝によって分離されたゲート電極をもつYBa2Cu3O7-δナノチャネル素子において観測された電界効果
守屋雅隆; 新タ智啓; 河原木槙二; 水柿義直
Poster presentation, Japanese, 応用物理学会 第62回応用物理学会春季学術講演会, 応用物理学会, 神奈川県平塚市, Domestic conference
12 Mar. 2015

Polarity Reversal of Tunnel Magnetoresistance Observed in Lateral Ferromagnet-Superconductor-Ferromagnet Single-Electron Transistor
Y. Mizugaki; M. Takiguchi; H. Shimada
Oral presentation, English, The Joint Symposium of 9th International Symposium on Medical, Bio- and Nano-Electronics, and 6th International Workshop on Nanostructures & Nanoelectronics, Research Institute of Electrical Communication, Tohoku University, Sendai, Japan, International conference
02 Mar. 2015

量子電流ミラー効果に基づく高精度な電流整数倍器の実現に向けた研究
武田晃一; 宮脇健至; ガンドロシュラ スリニワス; 石田千尋; 萩原彩乃; 水柿義直; 島田 宏
Oral presentation, Japanese, 電子情報通信学会技術研究報告（超伝導エレクトロニクス）, 電子情報通信学会, 東京都港区, Domestic conference
22 Jan. 2015

Splitter-Based SFQ Sequential Read Only Memory
K. Sawada; T. Watanabe; Y. Urai; Y. Mutoh; Y. Mizugaki
Oral presentation, English, Superconducting SFQ VLSI Workshop (SSV 2014), Kobe, Japan, International conference
02 Dec. 2014

Magnetization switching assisted by bias voltage in a single electron transistor comprising an aluminum island and cobalt leads
A. Elarabi; M. Moriya; H. Shimada; Y. Mizugaki
Poster presentation, English, The 9th International Symposium on Intrinsic Josephson Effects and THz Plasma Oscillations in High-Tc Superconductors (THz-PLASMA 2014), Kyoto, Japan, International conference
02 Dec. 2014

7-bit Single-Flux-Quantum Maximum-Length-Sequence Generator Implemented with 32-Fold Pulse Number Multiplier
Y. Mutoh; K. Sawada; T. Watanabe; Y. Urai; Y. Mizugaki
Poster presentation, English, Superconducting SFQ VLSI Workshop (SSV 2014), Kobe, Japan, International conference
01 Dec. 2014

Design and Operation of a 9-Bit Single-Flux-Quantum Pulse-Frequency Modulation Digital-to-Analog Converter
Y. Mizugaki; Y. Takahashi; H. Shimada; M. Maezawa
Oral presentation, English, 27th International Symposium on Superconductivity, ISTEC, Funabori, Tokyo, Japan, International conference
27 Nov. 2014

4-bit Bipolar Triangle Voltage Waveform Generator Using Single-Flux-Quantum Circuit
T. Watanabe; Y. Takahashi; H. Shimada; M. Maezawa; Y. Mizugaki
Poster presentation, English, 27th International Symposium on Superconductivity, ISTEC, Funabori, Tokyo, Japan, International conference
27 Nov. 2014

Quantum Interference in DC-SQUIDs Comprising Two Sub-Micron Aluminum Josephson Junctions: Deviation from Classical Model
K. Miura; K. Kikuchi; H. Shimada; Y. Mizugaki
Poster presentation, English, 27th International Symposium on Superconductivity, ISTEC, Funabori, Tokyo, Japan, International conference
27 Nov. 2014

SiO援用Dolan法で作製した微小Alトンネル接合列内での接合特性の均一性
徳山貴斗; 島田 宏; 水柿義直
Oral presentation, Japanese, 2014年度秋季 第90回 低温工学・超電導学会研究発表会, 低温工学・超電導学会, 福島県福島市, Domestic conference
05 Nov. 2014

量子電流ミラー効果における電流誘引過程の非局所性
武田晃一; 水柿義直; 島田 宏
Oral presentation, Japanese, 日本物理学会2014年秋季大会, 日本物理学会, 中部大学春日井キャンパス（愛知県春日井市松本町1200）, Domestic conference
09 Sep. 2014

Numerical Demonstration of Single-Electron Inverter with Input Discretizer
Tran Thi Thu Huong; H. Shimada; Y. Mizugaki
Oral presentation, English, JSAP Autumn Meeting, JSAP, Sapporo, Domestic conference
Sep. 2014

サブミクロンAl 接合を用いたdc-SQUID の量子干渉パターンに見られる 古典的理論との差異
三浦晃司; 菊池健人; 島田 宏; 水柿義直
Oral presentation, Japanese, JSAP Autumn Meeting, JSAP, Sapporo, Domestic conference
Sep. 2014

オンチップのパルス電流生成器による磁気結合dc/SFQ変換器のパルス応答検証
渡邉智希; 浦井芳彰; 島田 宏; 水柿義直
Oral presentation, Japanese, JSAP Autumn Meeting, JSAP, Sapporo, Domestic conference
Sep. 2014

パルス数増倍器を入力に備えた200倍DFQアンプの高周波入力応答
浦井芳彰; 高橋義隆; 島田 宏; 前澤正明; 水柿義直
Oral presentation, Japanese, JSAP Autumn Meeting, JSAP, Sapporo, Domestic conference
Sep. 2014

微小なAl/AlOx/V接合を用いた超伝導単一電子トランジスタ
宮脇健至; 水柿義直; 島田 宏
Oral presentation, Japanese, JSAP Autumn Meeting, JSAP, Sapporo, Domestic conference
Sep. 2014

9ビット・2.5 mVpp 単一磁束量子パルス周波数変調型ディジタル−アナログ変換器の試作と動作検証
水柿義直; 高橋義隆; 島田 宏; 前澤正明
Oral presentation, Japanese, 電子情報通信学会ソサイエティ大会, 電子情報通信学会, 徳島市, Domestic conference
Sep. 2014

Prototypes of Single-Chip Voltage Waveform Generators Based on SFQ Pulse-Frequency Modulation
Y. Mizugaki; K. Kuroiwa; Y. Sato; Y. Takahashi; H. Shimada; M. Maezawa
Oral presentation, Japanese, 電子情報通信学会技術研究報告（超伝導エレクトロニクス）, 電子情報通信学会, 東京, Domestic conference
23 Jul. 2014

Nbインライン接合でのゼロ・クロッシング・シャピロ・ステップ生成
水柿義直; 高橋春菜; 島田 宏
Oral presentation, Japanese, 応用物理学会,第61回応用物理学会春季学術講演会
18 Mar. 2014

超伝導体にバナジウムを用いたマイクロ冷凍機の試作と動作検証
井上裕太; 島田 宏; 守屋雅隆; 水柿義直
Oral presentation, Japanese, 応用物理学会,第61回応用物理学会春季学術講演会
Mar. 2014

入力離散化器を備えた単電子トランジスタの離散的入出力特性の実験検証
滝口将志; 三浦晃司; 島田 宏; 水柿義直
Oral presentation, Japanese, 応用物理学会,第61回応用物理学会春季学術講演会
Mar. 2014

磁場応答が非対称なジョセフソン接合でのゼロ・クロッシング・シャピロ・ステップ生成
高橋春菜; 守屋雅隆; 徳山貴斗; 島田 宏; 水柿義直
Oral presentation, Japanese, 電子情報通信学会,超伝導エレクトロニクス研究会
23 Jan. 2014

Nonlinear Characteristics of RF-Driven Asymmetric DC-SQUID Applied for Digital-to-Analog Conversion
Y. Mizugaki
Invited oral presentation, English, The 7th East Asia Symposium on Superconductor Electronics (EASSE 2013), EASSE organization committee, Taipei, Taiwan, International conference
Oct. 2013

Demonstration of a 1000-fold voltage multiplier using double-flux-quantum generation
Y. Mizugaki; Y. Sato; H. Shimada; M. Maezawa
Invited oral presentation, English, 11th European Conference on Applied Superconductivity (EUCAS 2013), European Society of Applied Superconductivity (ESAS), Genoa, Italy, International conference
Sep. 2013

微小ジョセフソン接合列におけるBloch振動と電流プラトー
出口智明; 鹿取俊介; Srinivas Gandrothula; 水柿義直; 島田 宏
Oral presentation, Japanese, 応用物理学会,第74回応用物理学会秋季学術講演会
Sep. 2013

SiO援用によるAlトンネル接合の面積縮小化とクーロンブロッケイド温度計への応用
牛澤旭人; 滝口将志; 島田 宏; 守屋雅隆; 水柿義直
Oral presentation, Japanese, 応用物理学会,第74回応用物理学会秋季学術講演会
Sep. 2013

超伝導島電極を有する強磁性単一電子トランジスタにおける磁気抵抗比のバイアス電圧依存性
滝口将志; 島田 宏; 水柿義直
Oral presentation, Japanese, 応用物理学会,第74回応用物理学会秋季学術講演会
Sep. 2013

微小ジョセフソン接合列間の量子電流ミラー効果に見られる二面性
島田 宏; 武田晃一; 水柿義直
Oral presentation, Japanese, 電子情報通信学会,2013年電子情報通信学会ソサイエティ大会
Sep. 2013

量子電流ミラー効果に基づく微小電流の整数倍器
武田晃一; 水柿義直; 島田 宏
Oral presentation, Japanese, 電子情報通信学会,2013年電子情報通信学会ソサイエティ大会
Sep. 2013

単一量子トンネリングを利用した間欠発振デバイスの動作実証と情報処理回路への応用
水柿義直
Others, Japanese, 2013 旭硝子財団 助成研究発表会, 公益財団法人 旭硝子財団
Jul. 2013

DC/SFQ変換器をSFQ入力に用いた1000倍電圧増倍回路の増倍率評価
佐藤裕介; 守屋雅隆; 島田 宏; 水柿義直; 前澤正明
Oral presentation, Japanese, 電子情報通信学会,総合大会
Mar. 2013

非対称SQUIDの平衡3進配列を用いた3ビット・ディジタル－両極性アナログ電圧変換器の試作
水柿義直; 守屋雅隆; 瀧澤宏幸
Oral presentation, Japanese, 電子情報通信学会,総合大会
Mar. 2013

Al/AlO_x_/V Josephson接合を用いた単一Cooper対素子
宮脇健至; 萩原彩乃; 小谷祥生; 水柿義直; 島田 宏
Oral presentation, Japanese, 電子情報通信学会,総合大会
Mar. 2013

非対称2接合SQUIDでのゼロ・クロッシング・シャピロ・ステップを利用した3bit平衡3進ディジタル‐アナログ変換器
守屋雅隆; 瀧澤宏幸; 水柿義直
Oral presentation, Japanese, 応用物理学会,第60回春季学術講演会
Mar. 2013

微小Josephson接合列を用いた電流整数倍器の高精度化
武田晃一; S. Gandrothula; 水柿義直; 島田 宏
Oral presentation, Japanese, 応用物理学会,第60回春季学術講演会
Mar. 2013

散逸要素を組み込んだ単一電子素子・単一磁束量子素子での間欠発振
水柿義直
Oral presentation, Japanese, 電子情報通信学会,電子デバイス研究会&シリコン材料・デバイス研究会
Feb. 2013

超伝導島電極を有する強磁性SETにおける磁気抵抗比の極性とトンネル抵抗値の相関
滝口将志; 守屋雅隆; 島田 宏; 水柿義直
Oral presentation, Japanese, 電子情報通信学会,電子デバイス研究会&シリコン材料・デバイス研究会
Feb. 2013

アンダーダンプ接合でのSFQ反射を利用する1000倍電圧増倍器の動作検証
佐藤裕介; 守屋雅隆; 島田 宏; 水柿義直; 前澤正明
Oral presentation, Japanese, 電子情報通信学会,超伝導エレクトロニクス研究会
Jan. 2013

Al-SiO-Al三方向斜め蒸着による微小トンネル接合の作製
牛澤旭人; 滝口将志; 島田 宏; 守屋雅隆; 水柿義直
Public symposium, Japanese, 第9回合同シンポジウム ナノ未来材料とコヒーレント光科学, 東京農工大学・電気通信大学, 調布
Dec. 2012

微小Josephson 接合列を用いた電流整数倍器の研究
武田晃一; 萩原彩乃; Srinivas Gandrothula; 水柿義直; 島田 宏
Public symposium, Japanese, 第9回合同シンポジウム ナノ未来材料とコヒーレント光科学, 東京農工大学・電気通信大学, 調布
Dec. 2012

6-bit可変型SFQパルス数増倍回路の設計と動作検証
高橋義隆; 守屋雅隆; 島田 宏; 水柿義直; 前澤正明
Oral presentation, Japanese, 電子情報通信学会,超伝導エレクトロニクス研究会
Oct. 2012

強磁性体－超伝導体－強磁性体電極を持つ単一電子トランジスタにおけるトンネル磁気抵抗比の温度依存性
滝口将志; 島田 宏; 守屋雅隆; 水柿義直
Oral presentation, Japanese, 電子情報通信学会,2012年ソサイエティ大会
Sep. 2012

サブミクロンAl接合SQUIDの量子干渉パターンに見られる帯電効果の影響
水柿義直; 菊池健人; 島田 宏
Oral presentation, Japanese, 電子情報通信学会,2012年ソサイエティ大会
Sep. 2012

RSQUIDにおける間欠発振現象の間接的確認
水柿義直
Oral presentation, Japanese, 応用物理学会,第73回学術講演会
Sep. 2012

アンダーダンプ接合でのSFQ反射を利用した100倍電圧増倍器の動作検証
佐藤裕介; 守屋雅隆; 島田 宏; 水柿義直; 前澤正明
Oral presentation, Japanese, 応用物理学会,第73回学術講演会
Sep. 2012

Currents steps in a mesoscopic Josephson junction embedded in a Josephson-junction network
S. Gandrothula; Y. Mizugaki; H. Shimada
Oral presentation, English, 応用物理学会,平成24年春季第59回応用物理学関係連合講演会
Mar. 2012

アンダーダンプ接合でのSFQ反射を利用する電圧増倍器の増倍率評価
佐藤裕介; 守屋雅隆; 島田 宏; 水柿義直; 前澤正明
Oral presentation, Japanese, 電子情報通信学会,2012年電子情報通信学会総合大会
Mar. 2012

非対称2接合SQUIDでのゼロ・クロッシング・シャピロ・ステップを利用した両極性ディジタル‐アナログ変換器の試作
守屋雅隆; 瀧澤宏幸; 水柿義直
Oral presentation, Japanese, 電子情報通信学会,2012年電子情報通信学会総合大会
Mar. 2012

微小ジョセフソン接合列間の電流誘引現象
石田千尋; 水柿義直; 島田 宏
Oral presentation, Japanese, 日本物理学会,第67回年次大会
Mar. 2012

SFQパルス周波数変調に基づく電圧波形合成回路
黒岩桂介; 守屋雅隆; 島田 宏; 水柿義直; 前澤正明
Invited oral presentation, Japanese, 超伝導エレクトロニクス研究会, 電子情報通信学会
Jan. 2012

強く容量結合した微小Josephson接合列における電流誘引現象
石田千尋; 水柿義直; 島田 宏
Public symposium, Japanese, 第8回合同シンポジウム ナノ未来材料とコヒーレント光科学, 東京農工大学・電気通信大学, 小金井
Dec. 2011

SQUID共振を利用したサブミクロンAl接合容量の測定
菊池健人; 守屋雅隆; 島田 宏; 水柿義直
Oral presentation, Japanese, 電子情報通信学会,超伝導エレクトロニクス研究会
Oct. 2011

非対称2接合SQUIDでのゼロ・クロッシング・シャピロ・ステップ生成を利用するディジタル‐アナログ変換器の試作
水柿義直; 近藤直樹; 守屋雅隆
Oral presentation, English, 応用物理学会,第72回応用物理学会学術講演会
Sep. 2011

シュミットトリガ動作をする単一電子デバイスの提案とパラメータ設計
滝口将志; 守屋雅隆; 島田 宏; 水柿義直
Oral presentation, English, 応用物理学会,第72回応用物理学会学術講演会
Sep. 2011

6ビット単一磁束量子パルス数可変増倍回路の設計と動作検証
水柿義直; 斎藤淳; 守屋雅隆; 前澤正明
Oral presentation, Japanese, 電子情報通信学会,2011年電子情報通信学会ソサイエティ大会
Sep. 2011

パルス周波数変調型3ビットRSFQ-D/A変換器による4段擬似正弦波形合成
黒岩桂介; 守屋雅隆; 島田 宏; 水柿義直; 前澤正明
Oral presentation, Japanese, 電子情報通信学会,2011年電子情報通信学会ソサイエティ大会
Sep. 2011

Nb 超伝導集積チップでの抵抗体の発熱による温度上昇の評価
黒岩桂介; 門脇正樹; 守屋雅隆; 島田宏; 水柿義直
Oral presentation, Japanese, 電子情報通信学会,2011年総合大会
Mar. 2011

10-time current multiplier based on the Quantum Current Mirror
S. Gandrothula; Y. Mizugaki; H. Shimada
Oral presentation, English, 応用物理学会,平成23年春季第58回応用物理学関係連合講演会
Mar. 2011

Influence of a spin polarized current on the magnetization reversal in a Co/Al/Co single electron transistor
A. Elarabi; M. Moriya; H. Shimada; Y. Mizugaki
Oral presentation, English, 応用物理学会,平成23年春季第58回応用物理学関係連合講演会
Mar. 2011

散逸を含む系での単一量子トンネリングと間欠振動現象に関する数値計算
水柿義直
Public symposium, Japanese, 東北大学電気通信研究所共同プロジェクト研究会「環境負荷低減に資する超伝導計算機技術に関する研究」, 東北大学・電気通信研究所, 仙台
Feb. 2011

SQUID共振を利用したサブミクロンAl接合容量の測定
菊池健人; 守屋雅隆; 島田 宏; 水柿義直
Oral presentation, Japanese, 電子情報通信学会,電子デバイス研究会
Feb. 2011

Current multipliers based on the quantum current mirror
S. Gandrothula; C. Ishida; Y. Mizugaki; H. Shimada
Public symposium, English, 第7回合同シンポジウム ナノ未来材料とコヒーレント光科学, 東京農工大学・電気通信大学, 調布
Dec. 2010

Magnetization reversal dependence on bias voltage in Co/Al/Co single electron transistor
A. Elarabi; M. Moriya; H. Shimada; Y. Mizugaki
Public symposium, English, 第7回合同シンポジウム ナノ未来材料とコヒーレント光科学, 東京農工大学・電気通信大学, 調布
Dec. 2010

制御電流注入型サブミクロンAl接合SQUIDの試作とループインダクタンス評価
菊池健人; 守屋雅隆; 島田 宏; 水柿義直
Oral presentation, Japanese, 応用物理学会,第71回応用物理学会学術講演会 講演予稿集
Sep. 2010

分流抵抗器付きゲートを有する単一電子トランジスタでの間欠振動現象に関する数値計算
水柿義直
Oral presentation, Japanese, 応用物理学会,第71回応用物理学会学術講演会 講演予稿集
Sep. 2010

Numerical Demonstration of Relaxation Oscillation in Single-Electron Transistor with Resistively-Shunted Gate
Y. Mizugaki
Public symposium, English, Linnaues Colloquium on Engineered Quantum Systems, Chalmers University of Technology, Gothenburg
Sep. 2010

Stacked-SQUIDを利用した電圧増倍回路の動作検証
田中丈之; 斎藤淳; 小林忠行; 守屋雅隆; 水柿義直; 前澤正明
Oral presentation, Japanese, 電子情報通信学会,2010年総合大会
Mar. 2010

強磁性リード電極を有する単一電子トランジスタでの磁気抵抗比増大効果の観測
田村伸行; 菊池健人; 守屋雅隆; 小林忠行; 島田 宏; 水柿義直
Oral presentation, English, 電子情報通信学会,電子デバイス研究会
Feb. 2010

DA変換器応用を目指したパルス数可変増倍回路の設計と動作検証
斎藤淳; 田中丈之; 守屋雅隆; 小林忠行; 水柿義直; 前澤正明
Oral presentation, Japanese, 電子情報通信学会,超伝導エレクトロニクス研究会
Jan. 2010

超伝導体を島電極に持つ強磁性単一電子トランジスタにおける磁気抵抗比増大の観測
田村伸行; 菊池健人; 守屋雅隆; 小林忠行; 島田宏; 水柿義直
Public symposium, Japanese, 第6回合同シンポジウム 「ナノ未来材料とコヒーレント光科学」, 東京農工大学・電気通信大学, 小金井
Dec. 2009

強磁性単一電子トランジスタの磁気抵抗異常増大
安部裕介; 島田 宏; 水柿義直
Public symposium, Japanese, 第6回合同シンポジウム 「ナノ未来材料とコヒーレント光科学」, 東京農工大学・電気通信大学, 小金井
Dec. 2009

量子電流ミラー効果に基づく微小電流整数倍器の試作
島田 宏; 中村謙太; 水柿義直
Public symposium, Japanese, 第6回合同シンポジウム 「ナノ未来材料とコヒーレント光科学」, 東京農工大学・電気通信大学, 小金井
Dec. 2009

超伝導島電極を有する強磁性単一電子トランジスタでのスピン依存伝導
水柿義直
Public symposium, Japanese, 平成21年度東北大学電気通信研究所共同プロジェクト研究「環境負荷低減に資する超伝導計算機技術に関する研究」研究会, 東北大学電気通信研究所, 仙台
Nov. 2009

a軸配向YBCO薄膜を用いた膜厚変化型ブリッジの作製と特性 IV
守屋雅隆; 牧野友哉; 水柿義直; 小林忠行
Oral presentation, Japanese, 応用物理学会,第70回応用物理学会学術講演会
Sep. 2009

超伝導体を島電極に持つ強磁性単一電子トランジスタにおける磁気抵抗比増大の観測
田村伸行; 菊池健人; 守屋雅隆; 小林忠行; 島田 宏; 水柿義直
Oral presentation, Japanese, 応用物理学会,第70回応用物理学会学術講演会
Sep. 2009

ヒステリシスのないジョセフソン接合を用いた間欠発振器に関する数値計算
水柿義直; 柏竜太; 小林忠行
Oral presentation, Japanese, 電子情報通信学会,2009年総合大会
Mar. 2009

分岐器と合流器を用いた単一磁束量子パルス数増倍器の設計
河合章生; 田中丈之; 斎藤淳; 守屋雅隆; 小林忠行; 水柿義直
Oral presentation, Japanese, 電子情報通信学会,2009年総合大会
Mar. 2009

SQUIDスタックを利用した電圧増倍回路セル
田中丈之; 小林忠行; 守屋雅隆; 水柿義直; 前澤正明
Oral presentation, Japanese, 電子情報通信学会,2009年総合大会
Mar. 2009

入力離散化器付き単一電子トランジスタおよびターンスタイルの特性
滝口将志; 速水翔太; 大塚正喜; 河合章生; 守屋雅隆; 小林忠行; 島田 宏; 水柿義直
Oral presentation, Japanese, 電子情報通信学会,シリコン材料・デバイス研究会(SDM)・電子デバイス研究会（ED）合同研究会
Feb. 2009

Nb集積回路における平行線路間の相互インダクタンス評価
河合章生; 柏 竜太; 守屋雅隆; 小林忠行; 水柿義直
Oral presentation, Japanese, 電子情報通信学会,電子情報通信学会技術研究報告（超伝導エレクトロニクス）
Oct. 2008

近似モデルを用いた超伝導薄膜積層構造のインダクタンス計算
河合章生; 柏竜太; 田中丈之; 守屋雅隆; 小林忠行; 水柿義直
Oral presentation, Japanese, 電子情報通信学会,2008年エレクトロニクスソサイエティ大会
Sep. 2008

2ヶ所で接続された2層グラウンド間での磁束量子化と磁気遮蔽効果
水柿義直; 柏竜太; 河合章生; 守屋雅隆; 小林忠行
Oral presentation, Japanese, 電子情報通信学会,2008年エレクトロニクスソサイエティ大会
Sep. 2008

Inductance of Superconducting Stripline Sandwiched between Two Ground Planes
Y. Mizugaki; R. Kashiwa; A. Kawai; M. Moriya; T. Kobayashi
Public symposium, English, Superconducting SFQ VLSI Workshop (SSV 2008), MEXT SFQ Project and the JST-CREST SFQ Project, Yokohama
Mar. 2008

超伝導シールド層の接地間隔による相互インダクタンスの変化
柏竜太; 河合章生; 守屋雅隆; 宇佐美興一; 小林忠行; 水柿義直
Oral presentation, Japanese, 電子情報通信学会,総合大会
Mar. 2008

2次ステップを利用するジョセフソン電圧増倍回路の多段接続動作
水柿義直; 生田目洋子; 田中丈之; 守屋雅隆; 宇佐美興一; 小林忠行; 前澤正明
Oral presentation, Japanese, 電子情報通信学会,総合大会
Mar. 2008

単一電子箱を入力端子部に備えた単一電子トランジスタの入出力特性
滝口将志; 河合章生; 速水翔太; 守屋雅隆; 宇佐美興一; 小林忠行; 島田宏; 水柿義直
Oral presentation, Japanese, 応用物理学会,平成20年春季第55回応用物理学関係連合講演会
Mar. 2008

基板バイアスMPCVD法によるダイヤモンド薄膜からの電子放出特性（IV）
守屋雅隆; 星野達也; 宇佐美興一; 水柿義直; 小林忠行; 湯郷成美
Oral presentation, Japanese, 応用物理学会,平成20年春季第55回応用物理学関係連合講演会
Mar. 2008

a軸配向YBCO 薄膜を用いた膜厚変化形ブリッジの作製 III
橋本篤士; 丸山伸伍; 守屋雅隆; 水柿義直; 宇佐美興一; 小林忠行
Oral presentation, Japanese, 応用物理学会,平成20年春季第55回応用物理学関係連合講演会
Mar. 2008

量子電流ミラー効果を用いた微小電流２倍器
島田宏; 花堂純央; 水柿義直
Public symposium, Japanese, 第4回合同シンポジウム, 東京農工大学・電気通信大学
Dec. 2007

超伝導多層導波路の高密度三次元設計と評価
水柿義直; 守屋雅隆; 柏 竜太; 河合章生
Public symposium, Japanese, 平成19年度東北大学電気通信研究所共同プロジェクト研究会, 東北大学電気通信研究所, 仙台
Dec. 2007

交流電圧駆動された単一電子トランジスタでの直流電流生成と素子パラメータの最適化
水柿義直; 河合章生; 守屋雅隆; 宇佐美興一; 小林忠行; 島田宏
Oral presentation, Japanese, 応用物理学会,第68回応用物理学会学術講演会
Sep. 2007

量子電流ミラー効果に基づいた微小電流2倍器（II）
花堂純央; 島田宏; 水柿義直
Oral presentation, Japanese, 応用物理学会,第68回応用物理学会学術講演会
Sep. 2007

接地点を有する超伝導薄膜で磁気分離された超伝導ストリップライン間の相互インダクタンス
水柿義直; 柏竜太
Oral presentation, Japanese, 電子情報通信学会,超伝導エレクトロニクス研究会
Jul. 2007

GAを用いた広帯域マイクロストリップ線路BPFの設計に関する一考察
安藤芳晃; 和田光司; 水柿義直; 陳健; 谷井宏成
Oral presentation, Japanese, 電子情報通信学会,マイクロ波研究会
Mar. 2007

超伝導シールド層の接地位置の違いによる相互インダクタンスの変化
柏竜太; 守屋雅隆; 宇佐美興一; 小林忠行; 和田光司; 安藤芳晃; 陳健; 水柿義直
Oral presentation, Japanese, 電子情報通信学会,総合大会
Mar. 2007

2次元M型CIP法の数値分散に関する検討
安藤芳晃; 和田光司; 水柿義直; 陳健; 早川正士
Oral presentation, Japanese, 電子情報通信学会,総合大会
Mar. 2007

a軸配向NdBa$_2$Cu$_3$O$_{7-\delta}$薄膜を用いた膜厚変化形ブリッジの作製II
吉澤延之; 丸山伸伍; 守屋雅隆; 水柿義直; 宇佐美興一; 小林忠行
Oral presentation, Japanese, 応用物理学会,平成19年春季第54回応用物理学関係連合講演会
Mar. 2007

c軸配向NdBa$_2$Cu$_3$O$_{7-\delta}$薄膜を用いた膜厚変化形ブリッジの試作
常盤貴彦; 丸山伸伍; 守屋雅隆; 水柿義直; 宇佐美興一; 小林忠行
Oral presentation, Japanese, 応用物理学会,平成19年春季第54回応用物理学関係連合講演会
Mar. 2007

エタノール電気分解による陽極酸化アルミナ細孔内へのチューブ状カーボンの堆積
水柿義直; 小林恭平; 守屋雅隆; 宇佐美興一; 小林忠行
Oral presentation, Japanese, 応用物理学会,平成19年春季第54回応用物理学関係連合講演会
Mar. 2007

アルミ超伝導島電極を有するコバルト強磁性単電子トランジスタのスピン依存伝導特性
水柿義直; 波木井秀充; 守屋雅隆; 宇佐美興一; 小林忠行; 島田宏
Oral presentation, Japanese, 応用物理学会,平成19年春季第54回応用物理学関係連合講演会
Mar. 2007

量子電流ミラー効果に基づいた微小電流2倍器
島田宏; 河合卓磨; 水柿義直
Oral presentation, Japanese, 応用物理学会,平成19年春季第54回応用物理学関係連合講演会
Mar. 2007

Bi$_2$Sr$_2$CaCu$_2$O$_{y}$超伝導薄膜を用いたランプエッジ接合の作製
前嶋一利; 守屋雅隆; 水柿義直; 宇佐美興一; 小林忠行
Oral presentation, Japanese, 応用物理学会,平成19年春季第54回応用物理学関係連合講演会
Mar. 2007

量子電流ミラー効果を用いた微小電流２倍器
島田宏; 水柿義直
Public symposium, Japanese, 21世紀COEプログラム 第3回合同シンポジウム, 東京農工大学・電気通信大学, 調布
Dec. 2006

単一電子トランジスタを用いた微小強磁性金属の物性研究
石本英彦; 水柿義直; 島田宏
Public symposium, Japanese, 21世紀COEプログラム 第3回合同シンポジウム, 東京農工大学・電気通信大学, 調布
Dec. 2006

単一電子デバイスのクーロンブロッケイド領域設計法に関する研究
水田元紀; 島田宏; 水柿義直
Public symposium, Japanese, 21世紀COEプログラム 第3回合同シンポジウム, 東京農工大学・電気通信大学, 調布
Dec. 2006

強磁性体/超伝導体微小トンネル接合におけるスピン依存伝導特性
波木井秀充; 島田宏; 水柿義直
Public symposium, Japanese, 21世紀COEプログラム 第3回合同シンポジウム, 東京農工大学・電気通信大学, 調布
Dec. 2006

SQUIDの高周波応答とその応用
水柿義直
Public symposium, Japanese, 平成18年度東北大学電気通信研究所共同プロジェクト研究会, 東北大学電気通信研究所, 仙台
Dec. 2006

2次ステップを利用するジョセフソン電圧増倍回路
生田目洋子; 守屋雅隆; 宇佐美興一; 小林忠行; 水柿義直; 前澤正明
Oral presentation, Japanese, 電子情報通信学会,超伝導エレクトロニクス研究会
Nov. 2006

非対称2接合超伝導量子素子によるゼロ・クロッシング・ステップ生成
水柿義直; 加藤和行
Oral presentation, Japanese, 電子情報通信学会,超伝導エレクトロニクス研究会
Nov. 2006

DCリアクティブスパッタリング法によるAlドープZnO薄膜の基板バイアス効果
宇佐美興一; 本橋弘一; 布袋喬史; 黒川雄介; 守屋雅隆; 水柿義直; 小林忠行
Oral presentation, Japanese, 日本真空協会,真空に関する連合講演会
Nov. 2006

マイクロ波プラズマCVD法による円錐状カーボンの形成とその電界電子放出特性
松本裕司; 菅原雄大; 宇佐美興一; 守屋雅隆; 水柿義直; 小林忠行; 湯郷成美
Oral presentation, Japanese, 日本真空協会,真空に関する連合講演会
Nov. 2006

a軸配向NBCO下部電極を用いたランプエッジ接合の電気的特性
平塚雅; 守屋雅隆; 宇佐美興一; 水柿義直; 小林忠行
Oral presentation, Japanese, 低温工学・超電導学会,2006年度秋季低温工学・超電導学会
Nov. 2006

NBCO超伝導薄膜上に堆積したNiO層の特性
守屋雅隆; 今村太郎; 宇佐美興一; 水柿義直; 小林忠行
Oral presentation, Japanese, 低温工学・超電導学会,2006年度秋季低温工学・超電導学会
Nov. 2006

Single-Electron Devices and Circuits Electromagnetically Dual to Superconducting Josephson Electronics
Y. Mizugaki
Invited oral presentation, English, 2006 International Microprocesses and Nanotechnology Conference, Japan Society of Applied Physics, Kamakura, Japan, International conference
27 Oct. 2006

超伝導体を島電極とする強磁性単電子トランジスタのスピン依存伝導特性
波木井秀充; 守屋雅隆; 宇佐美興一; 小林忠行; 島田宏; 水柿義直
Oral presentation, Japanese, 電子情報通信学会,2006年ソサイエティ大会
Sep. 2006

非対称2接合SQUIDを用いたゼロ・クロス・ステップの生成
水柿義直; 加藤和行; 守屋雅隆; 宇佐美興一; 小林忠行
Oral presentation, Japanese, 電子情報通信学会,2006年ソサイエティ大会
Sep. 2006

Evaluation of ZnO membrane deposited on porous alumina using electrodeposition
Y. Nemoto; M. Moriya; K. Usami; T. Kobayashi; Y. Mizugaki
Oral presentation, Japanese, 応用物理学会,第67回応用物理学会学術講演会
Aug. 2006

Fabrication and electric field emission characteristic of conic carbon deposited by MPCVD
Y. Matsumoto; Y. Sugawara; K. Usami; M. Moriya; Y. Mizugaki; T. Kobayashi; N. Yugo
Oral presentation, Japanese, 応用物理学会,第67回応用物理学会学術講演会
Aug. 2006

RF properties of SQUIDs for DAC applications --Superconducting Electronics Research at the University of Electro-Communications (UEC Tokyo) --
Y. Mizugaki
Others, English, 日本学術振興会 超伝導エレクトロニクス第146委員会 第21回「ディジタル応用」分科会研究会
Apr. 2006

a軸配向YBCO薄膜を用いた膜厚変化形ブリッジの作製II
江飛; 影山尚人; 守屋雅隆; 水柿義直; 宇佐美興一; 小林忠行
Oral presentation, Japanese, 応用物理学会,第53回応用物理学関係連合講演会
Mar. 2006

単電子ターンスタイル素子を利用した電流ミラー回路の試作と評価
伊藤正史; 水田元紀; 守屋雅隆; 宇佐美興一; 小林忠行; 島田宏; 水柿義直
Oral presentation, Japanese, 応用物理学会,第53回応用物理学関係連合講演会
Mar. 2006

単電子ターンスタイル素子のクーロンブロッケイド領域に対する島電極自己容量の影響
水田元紀; 伊藤正史; 守屋雅隆; 宇佐美興一; 小林忠行; 島田宏; 水柿義直
Oral presentation, Japanese, 応用物理学会,第53回応用物理学関係連合講演会
Mar. 2006

高次ステップを利用するSFQ 電圧増倍回路の設計
生田目洋子; 加藤和行; 守屋雅隆; 宇佐美興一; 小林忠行; 水柿義直; 前澤正明
Oral presentation, Japanese, 電子情報通信学会,2006年電子情報通信学会総合大会
Mar. 2006

単電子ターンスタイル素子の電流ミラー回路応用
伊藤正史; 水田元紀; 島田宏; 水柿義直
Oral presentation, Japanese, 電気通信大学・東京農工大学,21世紀COEプログラム 第2回合同シンポジウム「ナノ未来材料とコヒーレント光化学」
Dec. 2005

基板バイアスMPCVD法によるダイヤモンド薄膜からの電界電子放出特性
松本裕司; 伊藤いずみ; 宇佐美興一; 守屋雅隆; 水柿義直; 小林忠行; 湯郷成美
Oral presentation, Japanese, 真空に関する連合講演会,第46回真空に関する連合講演会
Nov. 2005

陽極酸化アルミナ薄膜のナノピラー作製応用に関する研究
小林恭平; 守屋雅隆; 宇佐美興一; 小林忠行; 水柿義直
Oral presentation, Japanese, 真空に関する連合講演会,第46回真空に関する連合講演会
Nov. 2005

ａ軸配向ＮＢＣＯ薄膜を用いた膜厚変化形素子1
大河勇樹; 常盤貴彦; 守屋雅隆; 水柿義直; 宇佐美興一; 小林忠行
Oral presentation, Japanese, 低温工学・超電導学会,2005年秋季低温工学・超電導学会
Nov. 2005

Shapiro steps in an rf-field-driven SQUID and their applications
Y. Mizugaki
Invited oral presentation, English, International Workshop on Bio-magnetism & Taiwan-Japan Symposium on Superconductive Electronics, Taipei/Kaohsiung, Taiwan, International conference
Oct. 2005

Mutual Inductance Coupled through a Superconducting Magnetic Isolation Layer
Y. Mizugaki; H. Hakii; M. Moriya; K. Usami; T. Kobayashi
Oral presentation, Japanese, 電子情報通信学会,超伝導エレクトロニクス研究会
Oct. 2005

基板バイアスMPCVD法によるダイヤモンド薄膜からの電界電子放出特性 (III)
松本裕司; 宇佐美興一; 守屋雅隆; 水柿義直; 小林忠行; 湯郷成美
Oral presentation, Japanese, 応用物理学会,平成17年秋季第66回応用物理学会学術連合講演会
Sep. 2005

反応性直流スパッタリング法によるZnO薄膜の形成とAlドープ特性
布袋喬史; 宇佐美興一; 守屋雅隆; 水柿義直; 小林忠行; 中山時邦
Oral presentation, Japanese, 応用物理学会,平成17年秋季第66回応用物理学会学術連合講演会
Sep. 2005

Nb集積回路内の磁気シールド層による相互インダクタンス低減効果
波木井秀充; 守屋雅隆; 宇佐美興一; 小林忠行; 水柿義直
Oral presentation, English, 電子情報通信学会,2005年電子情報通信学会ソサイエティ大会
Sep. 2005

Current-Step-Like Structure in a YBCO Grain Boundary Josephson Junction under Microwave Irradiation
水柿義直; 陳健
Oral presentation, Japanese, Proceedings of the 2005 IEICE General Conference
Mar. 2005

Fabrication of the variable thickness bridges in a-axis oriented YBCO film
石田将崇; 江飛; 守屋雅隆; 水柿義直; 宇佐美興一; 小林忠行
Oral presentation, Japanese, 第52回応用物理学関係連合講演会 講演予稿集
Mar. 2005

サファイア基板上に作製したMIM型トンネルエミッタの特性
中村太陽; 宇佐美興一; 大霜宏介; 守屋雅隆; 水柿義直; 小林忠行; 後藤俊成
Oral presentation, Japanese, 第45回真空に関する連合講演会 講演予稿集
Oct. 2004

SiのRFプラズマ酸化膜の形成とMIS形トンネルエミッタへの応用(II)
萩生貴文; 家田義紀; 小山勇作; 宇佐美興一; 守屋雅隆; 水柿義直; 小林忠行; 後藤俊成
Oral presentation, Japanese, 第65回応用物理学会学術講演会 講演予稿集
Sep. 2004

基板バイアスMPCVD法によるダイヤモンド薄膜からの電界電子放出特性(II)
新妻和典; 白川悟史; 宇佐美興一; 守屋雅隆; 水柿義直; 小林忠行; 後藤俊成; 湯郷成美
Oral presentation, Japanese, 第65回応用物理学会学術講演会 講演予稿集
Sep. 2004

SiのRFプラズマ酸化膜の形成とMIS形トンネルエミッタへの応用(I)
萩生貴文; 家田義紀; 小山勇作; 宇佐美興一; 守屋雅隆; 水柿義直; 小林忠行; 後藤俊成
Oral presentation, Japanese, 第51回応用物理学関係連合講演会 講演予稿集
Mar. 2004

単電子帯電効果のデバイス応用とジョセフソンデバイスとの双対性
水柿義直
Others, Japanese, 東北大学電気通信研究所 平成15年度工学研究会（通研講演会）
Dec. 2003

直流スパッタリング法で傾斜SrTiO3基板上に堆積したBi系超伝導薄膜の特性
守屋雅隆; 後藤俊成; 宇佐美興一; 水柿義直; 小林忠行
Oral presentation, Japanese, 第６４回応用物理学会学術講演会予稿集第一分冊
Sep. 2003

サファイア基板上に作製したMIMトンネル素子の特性2
市川弘毅; 岡田創; 宇佐美興一; 守屋雅隆; 水柿義直; 小林忠行; 後藤俊成
Oral presentation, Japanese, 第６４回応用物理学会学術講演会予稿集第二分冊
Sep. 2003

基板バイアスMPCVD法によるダイヤモンド薄膜からの電解電子放出特性(Ⅰ)
新妻和典; 宇佐美興一; 守屋雅隆; 水柿義直; 小林忠行; 後藤俊成; 湯郷成美
Oral presentation, Japanese, 第６４回応用物理学会学術講演会予稿集第二分冊
Sep. 2003

電荷ソリトンで駆動された単電子ターンスタイルと電流ミラー効果
水柿義直; Per Delsing
Oral presentation, Japanese, 第64回応用物理学会学術講演会 講演予稿集
Aug. 2003

高周波磁界駆動型DC-SQUIDの動作モード解析
水柿義直; 杉 啓司
Oral presentation, Japanese, 2003年電子情報通信学会総合大会講演論文集
Mar. 2003

高周波磁界駆動型DC-SQUIDのシャピロ・ステップと量子干渉パターンの関係
水柿義直; 杉 啓司
Oral presentation, Japanese, 第50回応用物理学関係連合講演会 講演予稿集
Mar. 2003

アルミ系単電子トランジスタを用いたフラッシュ型A/D変換器の試作
水柿義直; Per Delsing
Invited oral presentation, Japanese, 第63回応用物理学会学術講演会, 応用物理学会, 新潟, Domestic conference
26 Sep. 2002

アルミ系単電子トランジスタを用いたフラッシュ型A/D変換器の試作
水柿義直; Per Delsing
Oral presentation, Japanese, 第62回応用物理学会学術講演会 講演予稿集
Sep. 2002

単一磁束量子ポンプによるゼロクロッシング・ステップの生成
水柿義直; 陳 健; 杉 啓司; 西方 啓; 中島健介; 山下 努
Oral presentation, Japanese, 2002年電子情報通信学会ソサイエティ大会講演論文集
Sep. 2002

SQUIDの高周波応答特性とその応用
水柿義直
Others, Japanese, 日本学術振興会 超伝導エレクトロニクス第146委員会 第15回「マイクロ波～光」分科会研究会
May 2002

SQUIDの高周波応答特性とその応用
水柿義直
Invited oral presentation, Japanese, 日本学術振興会 超伝導エレクトロニクス第146委員会 第15回「マイクロ波～光」分科会研究会
May 2002

3接合SQUIDの多相高周波磁束応答 － ゼロバイアス電流ステップの観測
水柿義直; 陳 健; 西方啓; 杉啓司; 中島健介; 山下努
Oral presentation, Japanese, 応用物理学会,第49回応用物理学関係連合講演会
Mar. 2002

Bi-2212ジョセフソンプラズマのNb/AlO_x_/Nb接合特性に及ぼす影響の検証
山田靖幸; 水柿義直; 中島健介; 山下努
Oral presentation, Japanese, 応用物理学会,第49回応用物理学関係連合講演会
Mar. 2002

コプレーナ共振器により励振されたDC-SQUIDの高周波応答
西方啓; 近藤忠之; 水柿義直; 陳 健; 中島健介; 山下努
Oral presentation, Japanese, 応用物理学会東北支部,第56回学術講演会
Dec. 2001

BSCCO固有ジョセフソン接合の磁束フロー状態における高周波応答
中尾光明; 栗形悠平; 水柿義直; 王華兵; 陳健; 中島健介; 山下努
Oral presentation, Japanese, 応用物理学会東北支部,第56回学術講演会
Dec. 2001

Bi2212単結晶上に作製したNb/AlOx/Nb接合の特性評価
山田靖幸; 水柿義直; 中島健介; 山下努
Oral presentation, Japanese, 応用物理学会東北支部,第56回学術講演会
Dec. 2001

Zero-crossing steps in a 3-junction SQUID controlled by RF magnetic flux
Y. Mizugaki; J. Chen; K. Nakajima; T. Yamashita
Oral presentation, English, 電子情報通信学会,技術研究報告（超伝導エレクトロニクス）
Oct. 2001

高周波磁束で励振された3接合SQUIDにおけるゼロバイアス電流ステップ
水柿義直; 陳 健; 中島健介; 山下努
Oral presentation, Japanese, 応用物理学会,平成13年秋季第62回応用物理学会学術講演会
Sep. 2001

2接合SQUIDへのRF磁場印加方法の改善
西方啓; 近藤忠之; 水柿義直; 陳 健; 中島健介; 山下努
Oral presentation, Japanese, 応用物理学会,平成13年秋季第62回応用物理学会学術講演会
Sep. 2001

LSCO薄膜における固有ジョセフソン接合特性の接合サイズ依存性
植松裕; 金相宰; 水柿義直; 陳 健; 中島健介; 山下努; 佐藤寿志; 内藤方夫
Oral presentation, Japanese, 応用物理学会,平成13年秋季第62回応用物理学会学術講演会
Sep. 2001

フラッシュ型4ビット単電子アナログ・ディジタル変換器の試作
水柿義直; Per Delsing; 山下努
Oral presentation, Japanese, 応用物理学会,平成13年春季第48回応用物理学関係連合講演会
Mar. 2001

LSCO固有接合の電圧電流特性上に観測されるジョセフソンプラズマ共振
植松裕; 佐々木登; 水柿義直; 中島健介; 山下努; 綿打敏司; 田中功
Oral presentation, Japanese, 応用物理学会,平成13年春季第48回応用物理学関係連合講演会
Mar. 2001

RF磁界変調型SQUIDのスイッチングデバイス応用
近藤忠之; 水柿義直; 中島健介; 山下努
Oral presentation, Japanese, 電子情報通信学会,技術研究報告（超伝導エレクトロニクス）
Oct. 2000

Nb/Al-AlO_x_/Nbジョセフソン接合を用いたBi_2_Sr_2_CaCu_2_O_x_ジョセフソンプラズマの検出
山田靖幸; 植松裕; 水柿義直; 中島健介; 山下努
Oral presentation, Japanese, 電子情報通信学会,技術研究報告（超伝導エレクトロニクス）
Oct. 2000

RF磁界駆動型DC-SQUIDのスイッチング素子特性
近藤忠之; 水柿義直; 陳 健; 中島健介; 山下努
Oral presentation, Japanese, 応用物理学会,第61回応用物理学会学術講演会
Sep. 2000

Nb/Al-AlO_x_/Nbジョセフソン接合を用いたBi_2_Sr_2_CaCu_2_O_x_ジョセフソンプラズマの検出
山田靖幸; 植松裕; 水柿義直; 中島健介; 山下努
Oral presentation, Japanese, 応用物理学会,第61回応用物理学会学術講演会
Sep. 2000

Sr置換量の異なるLSCO固有接合の電流電圧特性
植松裕; 立木隆; 佐々木登; 水柿義直; 中島健介; 山下努; 綿打敏司; 田中功
Oral presentation, Japanese, 応用物理学会,第61回応用物理学会学術講演会
Sep. 2000

高温超伝導体Bi_2_Sr_2_CaCu_2_O_x_単結晶上Nb/Al-AlO_x_/Nbジョセフソン接合の作製
山田靖幸; 植松裕; 水柿義直; 中島健介; 山下努
Oral presentation, Japanese, 応用物理学会,平成12年春季第47回応用物理学関係連合講演会
Mar. 2000

Typical microwave responses at 3 mm waveband in Bi_2_Sr_2_CaCu_2_O_8+x_ intrinsic Josephson junction stacks with an overlap structure
H. B. Wang; Y. Aruga; Y. Mizugaki; J. Chen; K. Nakajima; T. Yamashita
Oral presentation, English, 応用物理学会,平成12年春季第47回応用物理学関係連合講演会
Mar. 2000

YBCO粒界ジョセフソン接合を用いたrf磁界励起型dcSQUIDの評価
斉藤 桂; 水柿義直; A. I. ブラジンスキー; 中島健介; 山下努
Oral presentation, Japanese, 応用物理学会,平成12年春季第47回応用物理学関係連合講演会
Mar. 2000

RF磁界励起型DC SQUIDの論理デバイス応用
近藤忠之; 水柿義直; 陳健; 中島健介; 山下努
Oral presentation, Japanese, 応用物理学会,平成12年春季第47回応用物理学関係連合講演会
Mar. 2000

YBCO粒界ジョセフソン接合を用いたrf磁界励起型dcSQUIDの作製
斎藤桂; 水柿義直; チャン・コク・フー; 王華兵; 中島健介; A. I; ブラジンスキー; 山下努
Oral presentation, Japanese, 応用物理学会東北支部,第54回学術講演会
Dec. 1999

RF磁界駆動型SQUIDの高周波デバイス応用
近藤忠之; 水柿義直; 陳健; 中島健介; 山下努
Oral presentation, Japanese, 低温工学・超電導学会,1999年度秋季低温工学・超電導学会
Nov. 1999

Harmonic Frequency Mixings Using Bi_2_Sr_2_CaCu_2_O_8_ Intrinsic Josephson Junctions at 100GHz
H. B. Wang; Y. Aruga; Y. Mizugaki; J. Chen; K. Nakajima; T. Yamashita
Oral presentation, English, 応用物理学会,平成11年秋季第60回応用物理学会学術講演会
Sep. 1999

RF磁界励振SQUIDの高周波応答とそのデバイス応用
近藤忠之; 水柿義直; 陳健; 斎藤桂; 中島健介; 山下努
Oral presentation, Japanese, 応用物理学会,平成11年秋季第60回応用物理学会学術講演会
Sep. 1999

rf励起型dc-SQUIDスイッチングデバイス
斎藤桂; 水柿義直; 近藤忠之; 中島健介; 山下努
Oral presentation, Japanese, 応用物理学会,平成11年秋季第60回応用物理学会学術講演会
Sep. 1999

La_2-x_Sr_x_CuO_4_/Nbジョセフソン接合における超伝導ギャップ構造の観測
植松裕; 水柿義直; 中島健介; 山下努; 田中功; 兒嶋弘直
Oral presentation, Japanese, 応用物理学会,平成11年秋季第60回応用物理学会学術講演会
Sep. 1999

単一磁束量子を用いた位相モード乗算回路
柳沢潔; 小野美武; 中島康治; 水柿義直; 山下努; 東海林彰
Oral presentation, Japanese, 応用物理学会,第46回応用物理学関係連合講演会
Mar. 1999

LSCO単結晶における固有ジョセフソン効果
植松裕; 水柿義直; 中島健介; 山下努; 田中功; 兒嶋弘直
Oral presentation, Japanese, 応用物理学会,第46回応用物理学関係連合講演会
Mar. 1999

YBCO粒界接合におけるテラヘルツ応答の磁界変調
水柿義直; 陳健; 小林英介; 遠藤孝行; 中島健介; 山下努
Oral presentation, Japanese, 応用物理学会,第46回応用物理学関係連合講演会
Mar. 1999

東北大学における単一磁束量子素子の研究
水柿義直
Oral presentation, Japanese, 低温工学会,1998年度第4回超電導応用研究会シンポジウム
Feb. 1999

磁束量子遷移を利用した結合SQUIDリングオシレータ動作周波数の評価
水柿義直; 中島康治; 東海林彰
Oral presentation, Japanese, 電子情報通信学会,技術研究報告（超伝導エレクトロニクス）
Nov. 1998

単一磁束量子プロセッサと電圧モードRAM間のインターフェースに関する検討
水柿義直
Oral presentation, Japanese, 電子情報通信学会,1998年エレクトロニクスソサイエティ大会
Oct. 1998

固有ジョセフソン効果のパルスドライブ型電圧標準への応用
近藤忠之; 水柿義直; 中島健介; 山下努
Oral presentation, Japanese, 応用物理学会,第59回応用物理学会学術講演会
Sep. 1998

集束電子ビーム照射によるYBCO結合SQUIDの作製と評価
金相宰; 水柿義直; 陳健; 中島健介; 山下努
Oral presentation, Japanese, 応用物理学会,第45回応用物理学関係連合講演会
Mar. 1998

磁束量子遷移を利用したリングオシレータ動作周波数の評価方法
水柿義直; 中島康治
Oral presentation, Japanese, 電子情報通信学会,1998年総合大会
Mar. 1998

直接接地型位相モード論理回路
佐藤英毅; 小野美武; 水柿義直; 中島康治
Oral presentation, Japanese, 1998年総合大会
Mar. 1998

Nb/AlN_x_/Nbジョセフソン接合による位相モード回路の新しい集積化法の検討
小野美武; 水柿義直; 中島康治; 山下努
Oral presentation, Japanese, 電子情報通信学会,1998年総合大会
Mar. 1998

ジョセフソン接合の等価インダクタンスを利用した論理デバイスの特性
水柿義直; 小野美 武; 中島康治
Oral presentation, Japanese, 電子情報通信学会,技術研究報告（超伝導エレクトロニクス）
Nov. 1997

位相モードロジックの課題と今後の展望
中島康治; 小野美 武; 水柿義直
Oral presentation, Japanese, 応用物理学会,超伝導分科会第16回研究会
Nov. 1997

Phase Mode Logic and High Jc Junctions
K. Nakajima; Y. Mizugaki; T. Onomi; T. Yamashita
Invited oral presentation, English, International conference
May 1997

Fluxoid-type Logic Circuits
K. Nakajima; Y. Mizugaki; T. Onomi; T. Yamashita
Invited oral presentation, English, The CRL International Symposium; Physics and Applications of Mesoscopic Josephson Junctions, International conference
Mar. 1997

単一磁束量子動作におけるジョセフソン接合の高臨界電流密度化の検討
小野美武; 水柿義直; 山下努; 中島康治
Oral presentation, Japanese, 応用物理学会,第44回応用物理学関係連合講演会
Mar. 1997

高電流密度ジョセフソン接合のVm値の解析的表現
水柿義直; 中島康治
Oral presentation, Japanese, 電子情報通信学会,1996年ソサイエティ大会
Sep. 1996

位相モード論理ゲートによる2進カウンター回路
小野美 武; 水柿義直; 中島康治; 山下努
Oral presentation, Japanese, 応用物理学会,第43回応用物理学関係連合講演会
Mar. 1996

直流電流駆動結合SQUIDゲートとその順序回路への応用
水柿義直; 中島康治; 山下努
Oral presentation, Japanese, 電子情報通信学会,技術研究報告（超伝導エレクトロニクス）
Jul. 1995

抵抗接地位相モード論理回路の集積化
小野美 武; 水柿義直; 中島康治; 山下努
Oral presentation, Japanese, 電子情報通信学会,1994年秋季大会
Sep. 1994

抵抗接地位相モード論理ゲート
小野美 武; 水柿義直; 中島康治; 山下努
Oral presentation, Japanese, 応用物理学会,第55回応用物理学会学術講演会
Sep. 1994

超伝導シナプス回路とそのA/Dコンバータへの応用
水柿義直; 中島康治; 澤田康次; 山下努
Oral presentation, Japanese, 電子情報通信学会,技術研究報告（超伝導エレクトロニクス）
Jul. 1994

抵抗接地位相モード論理ゲートの試作
小野美 武; 水柿義直; 中島康治; 山下努
Oral presentation, Japanese, 電子情報通信学会,技術研究報告（超伝導エレクトロニクス）
Jul. 1994

接地可能な位相モード論理回路
小野美 武; 水柿義直; 中島康治; 山下努
Oral presentation, Japanese, 応用物理学会,第41回応用物理学関係連合講演会
Mar. 1994

超伝導神経回路用シナプス
水柿義直; 中島康治; 小宮崇博; 小野美 武; 澤田康次; 山下努
Oral presentation, Japanese, 応用物理学会,第41回応用物理学関係連合講演会
Mar. 1994

SQUIDによるインダクタンスの温度依存性の測定
小野美 武; 水柿義直; 中島康治; 山下努
Oral presentation, Japanese, 応用物理学会,第54回応用物理学会学術講演会
Sep. 1993

結合SQUIDによる超伝導神経回路網の集積化
水柿義直; 中島康治; 澤田康次; 山下努
Oral presentation, Japanese, 応用物理学会,第54回応用物理学会学術講演会
Sep. 1993

SQUIDによる超伝導薄膜のインダクタンスの評価
小野美 武; 水柿義直; 中島康治; 山下努
Oral presentation, Japanese, 電気関係学会東北支部,平成5年度電気関係学会東北支部連合大会
Sep. 1993

結合SQUIDのしきい値特性の解析と応用
水柿義直; 中島康治; 澤田康次; 山下努
Oral presentation, Japanese, 応用物理学会,第40回応用物理学関係連合講演会
Mar. 1993

超伝導ニューラル演算回路 (II)
水柿義直; 中島康治; 澤田康次; 山下努
Oral presentation, Japanese, 神経回路学会,第3回全国大会
Dec. 1992

フラクソンパルスを用いた超伝導神経回路
水柿義直; 中島康治; 澤田康次; 山下努
Oral presentation, Japanese, 電子情報通信学会,技術研究報告（非線形問題）
Oct. 1992

超伝導ニューラル演算回路
水柿義直; 中島康治; 澤田康次; 山下努
Oral presentation, Japanese, 神経回路学会,第2回全国大会
Dec. 1991

フラクソンパルスを用いた超伝導ニューラル演算回路の試作
水柿義直; 中島康治; 澤田康次; 山下努
Oral presentation, Japanese, 応用物理学会,第52回応用物理学会学術講演会
Oct. 1991

超伝導ニューラル演算回路の試作
水柿義直; 中島康治; 澤田康次; 山下努
Oral presentation, Japanese, 電子情報通信学会,技術研究報告（超伝導エレクトロニクス）
Oct. 1991

Nb-AlO_x_-Nb接合の新しい集積化法と超伝導ニューラル演算回路の試作
水柿義直; 中島康治; 澤田康次
Oral presentation, Japanese, 応用物理学会,第38回応用物理学関係連合講演会
Mar. 1991

理工学基礎実験
Oct. 2024 - Present

電子回路学
Oct. 2023 - Present

固体電子論
Apr. 2012 - Present
The University of Electro-Communications

Physics Laboratory
The University of Electro-Communications

Fundamentals of Solid State Electronics
The University of Electro-Communications

Linnaeus colloquium on engineered quantum systems
Chalmers University of Technology, Gothenburg, Sweden

Linnaeus colloquium on engineered quantum systems
Chalmers University of Technology, Gothenburg, Sweden

Special Lecture on Informatics and Engineering A
The University of Electro-Communications

Special Lecture on Informatics and Engineering A
電気通信大学

基盤理工学専攻基礎
The University of Electro-Communications

基盤理工学専攻基礎
電気通信大学

先進理工学基礎
The University of Electro-Communications

超伝導デバイス特論
The University of Electro-Communications

基礎科学実験Ａ
The University of Electro-Communications

微分積分学第一
The University of Electro-Communications

先進理工学基礎
The University of Electro-Communications

先進理工学基礎
電気通信大学

超伝導デバイス特論
The University of Electro-Communications

超伝導デバイス特論
電気通信大学

エンジニアリングデザイン２
The University of Electro-Communications

エンジニアリングデザイン２
電気通信大学

先進理工学専攻基礎
The University of Electro-Communications

先進理工学専攻基礎
電気通信大学

基礎科学実験Ａ
The University of Electro-Communications

基礎科学実験Ａ
電気通信大学

エンジニアリングデザイン１
The University of Electro-Communications

エンジニアリングデザイン１
電気通信大学

微分積分学第一
The University of Electro-Communications

微分積分学第一
電気通信大学

1996 - Present
The Institue of Electronics, Information and Communication Engineers

1990 - Present
Japan Society of Applied Physics

Optimal design method realizing the maximal limit of injection-locking and its applications.
Tanaka Hisaaki; KARASAWA Yoshio; HONJO Kazuhiko; MIZUGAKI Yoshinao
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), Injection-locking of nonlinear oscillators to an external periodic forcing is a fundamental phenomenon which adjusts their frequencies to that of an external forcing. Such injection-locking enables to stabilize the frequency of the oscillator, and it has a long history and produces a large variety of applications. In our research, we develop a method for maximizing the frequency range of an external forcing sustaining the injection-locked mode (i.e., locking range or synchronization band), based on our newly developed optimization theory. As a case study of optimizing synchronizability, we design the input waveforms that maximize locking ranges in an injection-locked Class-E oscillator, by using our optimization theory. Further, we verify the optimality of these inputs through systematic numerical calculations and experiments., 26286086
01 Apr. 2014 - 31 Mar. 2018

Study of nonlocal correlation of Cooper-pair tunnelings in systems of small Josephson junctions
SHIMADA Hiroshi; MIZUGAKI Yoshinao
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), We have experimentally shown that application of high-frequency radiation in a range 100 kHz-170 GHz to an array of small Josephson junctions weaken its Coulomb blockade of Cooper-pair tunneling and induce conductance in the array. There exists a correlation between currents in two arrays of small Josephson junctions separated by a distance of the order of 10 um. We have demonstrated that this can be understood quantitatively if we assume that a current in one array induces an ac voltage in the other array the magnitude of which is proportional to the square root of the current in the first. We have also investigated I-V characteristics of an array of small junctions connected to SQUID arrays which serve as its environmental impedance. We showed a clear Bloch oscillation when the environmental impedance was large as well as current plateaus superposed. The latter has turned out due to a kind of nonlocal interaction of the tunnelings in the SQUID arrays and those in the junction array., 24340067
01 Apr. 2012 - 31 Mar. 2015

Study on a high-precision current multiplier applicable to the quantum current standard
SHIMADA Hiroshi; MIZUGAKI Yoshinao
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), A small-current 10-time multiplier using one-dimensional arrays of small Al/Al2O3/Al Josephson junctions and based on the quantum-current-mirror effect have been fabricated and tested. It showed the expected 10-time current multiplication function. The accuracy of the multiplication, however, was not good. It was most likely due to the small coupling capacitance. In order to substantially improve the accuracy, a fabrication process of a large coupling capacitance between the arrays has been successfully installed. A 10-time current multiplier with strong coupling has been fabricated using the process. A strongly coupled quantum-current-mirror devices were also fabricated and tested, and the quantitative relationship between the strength of the coupling and accuracy of the current duplication has been obtained. In such devices current induction with 0 bias voltage on the secondary array has been observed for the first time. Moreover, novel reversal of the induced current was observed : the direction of the induced current was the same as the primary current(input current) while applied magnetic field was small and Cooper-pair tunneling was dominant, and it changed to the opposite direction when applied magnetic field was large and quasiparticle(or electron) tunneling was dominant., 21360040
2009 - 2011

アナログ－ディジタル変換素子
Patent right, 水柿義直, 滝口将志, 河合章生, 2008-22807, Date applied: 01 Feb. 2008, 国立大学法人 電気通信大学, 2009-182306, Date announced: 13 Aug. 2009, 5388002, Date issued: 18 Oct. 2013

カーボンチューブ及びカーボンチューブの製造方法
Patent right, 水柿義直, 小林恭平, 特願2005-241298, Date applied: 23 Aug. 2005, 国立大学法人電気通信大学, 2007-56295, Date announced: 08 Mar. 2007, 4625955, Date issued: 19 Nov. 2010

電流ミラー効果が生じる単電子デバイス
Patent right, 水柿義直, 2003-115352, Date applied: 21 Apr. 2003, 電気通信大学長 梶谷誠, 2004-319932, Date announced: 11 Nov. 2004, 3972099, Date issued: 22 Jun. 2007

多相高周波磁束駆動超伝導量子干渉素子
Patent right, 2001-117779,2001-117779, Date applied: 17 Apr. 2001, 2002-314155,2002-314155, Date announced: 25 Oct. 2002, 3525145,3525145, Date issued: 27 Feb. 2004

高周波磁束工藤超伝導量子干渉素子
Patent right, 平11-153173, Date applied: 01 Jun. 1999, 2000-338209,2000-338209, Date announced: 08 Dec. 2000, 3148741,3148741, Date issued: 12 Jan. 2001

出張講義（國學院大學久我山中学高等学校）
Lecturer, Visiting lecture
16 Oct. 2024 - 16 Oct. 2024

出張講義（千葉県立佐原高等学校）
Lecturer, Visiting lecture
03 Jul. 2024 - 03 Jul. 2024

出張講義（東京都立武蔵野北高等学校）
Lecturer, Visiting lecture
29 Sep. 2023 - 29 Sep. 2023

出張講義（東京電機大学高等学校）
Lecturer, Visiting lecture
21 Dec. 2022 - 21 Dec. 2022

出張講義（静岡県立韮山高等学校）
Lecturer, Visiting lecture
11 Dec. 2021 - 11 Dec. 2021

出張講義（埼玉県立川口北高等学校）
Lecturer, Visiting lecture
07 Oct. 2015 - 07 Oct. 2015

出張講義（茨城県立並木中等教育学校・高等学校）
Lecturer, Visiting lecture
19 Jun. 2013 - 19 Jun. 2013

出張講義（千葉県立佐原高等学校）
Lecturer, Visiting lecture
08 Jul. 2008 - 08 Jul. 2008

37th International Symposium on Superconductivity (ISS2024)
Competition etc, Panel chair etc, 05 Dec. 2024 - 05 Dec. 2024

17th Superconductive SFQ VLSI Workshop (SSV2024)
Competition etc, Planning etc, 11 Oct. 2024 - 12 Oct. 2024

電子情報通信学会 総合大会
Competition etc, Panel chair etc, 06 Mar. 2024 - 06 Mar. 2024

林誠也（博士前期課程2年） 電気通信大学 学生表彰(学長賞)
Mar. 2024 - Mar. 2024

福代大紀（情報理工学域4年） 一般社団法人目黒会 目黒会賞
Mar. 2023

佐藤健太（博士前期課程2年） 一般社団法人目黒会 目黒会賞
Mar. 2023

平松大樹（博士前期課程2年） 電気通信大学 学生表彰(学長賞)
Mar. 2023

佐藤健太（博士前期課程2年） 電気通信大学 学生表彰(学長賞)
Mar. 2023

浦江哲也（博士前期課...
浦江哲也（博士前期課程2年） 電気通信大学 学生表彰(学長賞)
2021 - 2021

瀬賀直功（博士前期課...
瀬賀直功（博士前期課程2年） 電気通信大学 学生表彰(学長賞)
2021 - 2021

林誠也（情報理工学域...
林誠也（情報理工学域4年） 一般社団法人目黒会 目黒会賞
2021 - 2021

瀬賀直功（博士前期課...
瀬賀直功（博士前期課程2年） 一般社団法人目黒会 目黒会賞
2021 - 2021

曽明裕太（博士前期課...
曽明裕太（博士前期課程2年） 電気通信大学 学生表彰(学長賞)
2020 - 2020

平田はるか（博士前期...
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