Search Results 1-20 of 626

  • Coexistence of Superconductivity and Charge Density Waves in Tantalum Disulfide: Experiment and Theory

    Kvashnin Y. , VanGennep D. , Mito M. , Medvedev S. A. , Thiyagarajan R. , Karis O. , Vasiliev A. N. , Eriksson O. , Abdel-Hafiez M.

    … Around Pc, we observe a superconducting dome with a maximum superconducting transition temperature Tc=9.1  K. … While a d wave and single-gap BCS prediction cannot describe the lower critical field Hc1 data, the temperature dependence of the Hc1 can be well described by a single-gap anisotropic s-wave order parameter. …

    Physical Review Letters (125), 186401-1-186401-6, 2020-10-27


  • Rapid Single-Flux-Quantum NOR Logic Gate Realized through the Use of Toggle Storage Loop

    Yoshinao MIZUGAKI , Koki YAMAZAKI , Hiroshi SHIMADA

    Parameter margins wider than ±28% were confirmed in simulation. …

    IEICE Transactions on Electronics E103.C(10), 547-549, 2020-10-01


  • Uniaxial-strain control of nematic superconductivity in SrxBi2Se3

    Kostylev Ivan , Yonezawa Shingo , Wang Zhiwei , Ando Yoichi , Maeno Yoshiteru

    液晶のような超伝導の配向パターンの制御に成功 --ネマティック超伝導のドメインエンジニアリングへ--. 京都大学プレスリリース. 2020-08-25.

    Nature Communications (11), 2020-08-24


  • Low temperature STM measurements of Pb atomic-layer on Si(100) substrate  [in Japanese]

    Ren Toki , Sato Yudai , Haze Masahiro , Hasegawa Yukio

    <p>半導体基板上に形成された単原子層超伝導相において、ステップは渦糸を排斥したりピン留めしたりなど系により様々に振る舞うが、どのようなパラメータに依存してその振る舞いが決定されるかは明らかではない。そこで、基板による違いを明らかにするため、Si(100)基板上に形成されたPb単原子層に着目し、STM測定を行った。また、わずかな違いで構造が変化するPbの蒸着量を制御するための自動制御機 …

    Abstract book of Annual Meeting of the Japan Society of Vacuum and Surface Science 2020(0), 42, 2020


  • Rapid Single-Flux-Quantum NOR Logic Gate Realized through the Use of Toggle Storage Loop

    MIZUGAKI Yoshinao , YAMAZAKI Koki , SHIMADA Hiroshi

    Parameter margins wider than ±28% were confirmed in simulation. …

    IEICE Transactions on Electronics E103.C(10), 547-549, 2020


  • The search for new superconducting materials using machine learning:Expectations for the 21st century Matthias Law  [in Japanese]

    MATSUMOTO Kaname , HORIDE Tomoya

    <p>初期の超伝導物質探索においてマティアス則が活躍した.マティアス則とは,遷移金属およびその合金の臨界温度<i>T</i><sub>c</sub>がある特定の物質パラメータの組み合わせにおいて極大になるという経験則で,多くの超伝導物質の発見につながった.ところが最近,計算機パワーの進展に伴い,全く新しい経験的な<i>T< …

    Oyo Buturi 89(4), 222-226, 2020


  • Superconductivity in a new layered triangular-lattice system Li2IrSi2

    Horigane K , Takeuchi K , Hyakumura D , Horie R , Sato T , Muranaka T , Kawashima K , Ishii H , Kubozono Y , Orimo S , Isobe M , Akimitsu J

    … We report on the crystal structure and superconducting properties of a novel iridium-silicide, namely Li2IrSi2. … We estimated the following superconducting parameters: lower critical field Hc1(0) ~ 42 Oe, upper critical field Hc2(0) ~ 1.7 kOe, penetration depth λ0 ~ 265 nm, coherence length ξ0 ~ 44 nm, and Ginzburg–Landau parameter κGL ~ 6.02. …

    New Journal of Physics (21), 093056, 2019-09-24


  • 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

    … In the new parameter set, we tuned the damping parameters of the Josephson junctions to realize proper propagation of SFQ pulses. … A 1000-fold DFQA designed with the new parameter set was fabricated using a 25-μ A/μ m 2 Nb/AlOx/Nb integration technology. …

    IEEE Transactions on Applied Superconductivity 29(5), 1400105-1-1400105-5, 2019-08


  • Depairing current density in superconductors

    Matsushita Teruo , Kiuchi Masaru

    … One of the reasons for the higher current densities is that those are obtained at the transition point to the normal state, while Tinkham obtained in the superconducting state far from the transition boundary. … Another reason is that the order parameter is larger than the equilibrium value, which contributes not only directly to a higher current density but also to a lower kinetic energy due to the current. …

    Applied Physics Express 12(6), 063003-1-063003-5, 2019-05-20

    IR  DOI 

  • High-energy Spin Fluctuation in Iron-based Superconductor LaFePO<sub>0.9</sub>  [in Japanese]

    Ishikado Motoyuki

    … <p>Spin fluctuations are widely believed to play an important role in the superconducting mechanisms of unconventional high-temperature superconductors, and they have been observed in various iron-based superconductors so far. … is an iron-based superconductor with a low superconducting transition temperature (<i>T</i><sub>c</sub> … = 5 K), where line nodes are observed in the superconducting order parameter. …

    hamon 29(4), 187-191, 2019


  • Critical Temperature in Bulk Ultrafine-Grained Superconductors of Nb, V, and Ta Processed by High-Pressure Torsion

    Nishizaki Terukazu , Edalati Kaveh , Lee Seungwon , Horita Zenji , Akune Tadahiro , Nojima Tsutomu , Iguchi Satoshi , Sasaki Takahiko

    … <p>This overview describes the progressive results of the superconducting critical temperature in bulk nanostructured metals (niobium, vanadium and tantalum) processed by high-pressure torsion (HPT). … Bulk nanostructured superconductors provide a new route to control superconducting property, because ultrafine-grain structures with a high density of grain boundaries, dislocations, and other crystalline defects modify the superconducting order parameter. …

    MATERIALS TRANSACTIONS 60(7), 1367-1376, 2019

    IR  J-STAGE 

  • Influence of Bifurcation Structures Revealed by Refinement of a Nonlinear Conductance in JosephsonJunction Element

    Miino Yuu , Ueta Tetsushi

    … We conduct a bifurcation analysis of a single-junction superconducting quantum interferometer with an external flux. … As a result, we reveal the bifurcation structure of the systems in a two-dimensional parameter plane. … By making a comparison between the linear and PWL cases, we find a difference in the shapes of their bifurcation sets in the two-dimensional parameter plane even though there are no differences in the one-dimensional bifurcation diagrams or the trajectories. …

    Complexity (2018), 8931525, 2018-12-02


  • The Dominant Role of Critical Valence Fluctuations on High Tc Superconductivity in Heavy Fermions

    Scheerer Gernot W. , Ren Zhi , Watanabe Shinji , Lapertot Gérard , Aoki Dai , Jaccard Didier , Miyake Kazumasa

    … The key novelty is the salient correlation between the superconducting transition temperature Tc and the valence instability parameter Tcr, which is in line with theory of enhanced valence fluctuations. … We develop the new idea that the optimum superconducting Tc of a given sample is mainly controlled by the compound's Tcr and limited by non-magnetic disorder. …

    npj Quantum Materials (3), 41-1-41-7, 2018-08-29


  • Quantum conductance-temperature phase diagram of granular superconductor KxFe2-ySe2

    Soares C. C. , ElMassalami M. , Yanagisawa Y. , Tanaka M. , Takeya H. , Takano Y.

    … It is now well established that the microstructure of Fe-based chalcogenide KxFe2−ySe2 consists of, at least, a minor (~15 percent), nano-sized, superconducting KsFe2Se2 phase and a major (~85 percent) insulating antiferromagnetic K2Fe4Se5 matrix. … On subjecting each of these systems to a varying control parameter (e.g. heat treatment, concentration x,y, or pressure p), one obtains an exotic normal-state and superconducting phase diagram. …

    Scientific Reports (8), 7041, 2018-05-04


  • Ginzburg–Landau Theory for Flux Phase and Superconductivity in t–J Model

    Kuboki Kazuhiro

    … Order parameter (OP) for the flux phase has direct coupling to a magnetic field, in contrast to the superconducting OP which has minimal coupling to a vector potential. …

    Journal of the Physical Society of Japan 87(2), 024703, 2018-02-15


  • Development of a low-cost and environment-friendly card-type chemical analysis device (Environmental Reseach Support Organization)  [in Japanese]

    池添 泰弘 , 武捨 秀紀 , 岡野 佑亮 , 種部 千遥 , 菅谷 将之 , 大森 一輝 , 浜崎 祐介 , Yasuhiro Ikezoe , Hidenori Musha , Yusuke Okano , Chiharu Tanebe , Masayuki Sugaya , Kazuki Ohmori , Yusuke Hamazaki

    … Therefore, purification of particles by such a parameter is very important, especially for the industrial applications. … If we use a superconducting magnet which can generate high magnetic field, e.g. 10 T, we can separate even non-magnetic materials because the magnetic force produced is also very strong in such a high field. …

    日本工業大学研究報告 = Report of researches, Nippon Institute of Technology 47(4), 17-20, 2018-02


  • Machine Parameter Estimation of Superconducting Transformer using a Genetic Algorithm Only for Inrush Current Waveform  [in Japanese]

    徳永 義孝

    低温工学 = Journal of Cryogenics and Superconductivity Society of Japan 53(1), 17-22, 2018

  • Machine Parameter Estimation of Superconducting Transformerusing a Genetic Algorithm Only for Inrush Current Waveform  [in Japanese]

    TOKUNAGA Yoshitaka

    … <p>This paper presents the estimation of machine parameters for a superconducting power transformer. … Using this estimation technique only for inrush current waveform, machine parameters and switching conditions of the superconducting transformer were estimated. …

    TEION KOGAKU (Journal of Cryogenics and Superconductivity Society of Japan) 53(1), 17-22, 2018


  • Antiferro-multipole Ordered State Associated with 4<i>f</i><sup>2</sup> Configuration in PrIr<sub>2</sub>Zn<sub>20</sub>  [in Japanese]

    Onimaru Takahiro , Iwasa Kazuaki

    … exhibits a superconducting transition at 0.05 K below a quadrupolar transition at 0.11 K. … ≤ 5 T down to 0.04 K to determine the order parameter expected for the non-Kramers ground state doublet. … The results indicate that the <i>O</i><sub>2</sub><sup>2</sup>-type quadrupole is the primary order parameter which entangles with other various multipolar degrees of freedom. …

    hamon 27(4), 144-147, 2017


  • Magnetic phenomena in UCoGe - URhGe system  [in Japanese]

    Pospíšil J. , Haga Y. , Kambe S. , Tokunaga Y. , Tateiwa N. , Miyake A. , Tokunaga M. , Yamamoto E.

    … We will discuss the effect of the magnetic moment re-orientation features along the b-axis on superconducting state of both parent compounds. … We have found the characteristic temperature Tmax as an important parameter of the system probably influencing the superconductivity re-entrance features. …

    Meeting Abstracts of the Physical Society of Japan 72.1(0), 1948-1948, 2017


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