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2012 Fiscal Year Annual Research Report

圧力誘起超伝導体の磁場侵入長の精密測定

Research Project

Project/Area Number 23654118
Research InstitutionKyoto University

Principal Investigator

松田 祐司  京都大学, 理学(系)研究科(研究院), 教授 (50199816)

Keywords異方的超伝導 / 磁場侵入長 / 圧力誘起超伝導 / 鉄系超伝導体 / 超伝導ギャップ
Research Abstract

本研究では、圧力中で100 mK以下の極低温までの超伝導体の磁場侵入長の変化を0.02 nmの高精度で測定できる装置を世界で初めて開発する事を目的とした.これにより圧力によって電子状態を連続的に変化させたとき非従来型の超伝導発現機構をもつ超伝導体の超伝導ギャップ関数の構造がどのように変化してゆくかを詳細に調べ、超伝導発現機構の理解を格段に進歩させることをめざした.一般にフォノン機構以外の非従来型の発現機構を持つ超伝導体の超伝導状態は不純物(ランダムネス)に非常に敏感である.電子状態は構成元素の化学置換により変化させることができるが、化学置換では系に不純物を導入してしまうため、しばしば超伝導ギャップ関数の構造決定が困難になってしまう. これに対し圧力効果では不純物の影響を変化させることなく、不純物効果を最小限に抑えた状態で、電子状態を連続的に変化させることができる.
本プロジェクトでは、圧力誘起型超伝導体の超伝導ギャップ構造の決定を目的として、トンネルダイオードを用いた超安定化発振回路により圧力下での極低温磁場侵入長測定法を確立し、特に鉄プニクタイド化合物の超流動電子密度の精密測定を圧力下で行った.圧力発生にはピストンシリンダー型の圧力セルを使用し、3 GPa程度までの圧力範囲で、希釈冷凍機温度までの極低温測定を行うことを試みた.現在の所、圧力シリンダー中でのトンネルダイオードの発信に成功している.しかしながら本測定を行うためには圧力シリンダーの温度を0.1 mK以内に安定にする必要がある事が判明し、この解決に思いのほか時間がかかってしまった.この問題を解決するために現在希釈冷凍機クライオスタットの試料ホルダー部分を作製し直しているところである.この問題の解決にはあと2-3ヶ月かかり、その後本研究で提案した実験を開始できると考えている

  • Research Products

    (30 results)

All 2013 2012

All Journal Article (20 results) (of which Peer Reviewed: 18 results) Presentation (9 results) (of which Invited: 8 results) Book (1 results)

  • [Journal Article] Searching for Zeros2013

    • Author(s)
      Y. Matsuda
    • Journal Title

      JPSJ Online-News and Comments [January 22, 2013]

      Volume: 82 Pages: 24707

    • Peer Reviewed
  • [Journal Article] Anomalous superfluid density in quantum critical superconductors2013

    • Author(s)
      K. Hashimoto
    • Journal Title

      Proc. Natl. Acad. Sci. USA

      Volume: 110 Pages: 3293-3297

    • DOI

      10.1073/pnas.1221976110

    • Peer Reviewed
  • [Journal Article] Interplane resistivity of isovalent doped BaFe2(As1-xPx)22013

    • Author(s)
      M. A. Tanatar
    • Journal Title

      Phys. Rev. B

      Volume: 87 Pages: 104506-1-5

    • DOI

      10.1103/PhysRevB.87.104506

    • Peer Reviewed
  • [Journal Article] Disorder, critical currents, and vortex pinning energies in isovalently substituted BaFe2(As1-xPx)22013

    • Author(s)
      S. Demirdis
    • Journal Title

      Phys. Rev. B

      Volume: 87 Pages: 094506-1-11

    • DOI

      10.1103/PhysRevB.87.094506

  • [Journal Article] Terahertz Conductivity of the Heavy-Fermion State in CeCoIn52013

    • Author(s)
      M. Scheffler
    • Journal Title

      J. Phys. Soc. Jpn.

      Volume: 82 Pages: 043712-1-5

    • DOI

      10.7566/JPSJ.82.043712

    • Peer Reviewed
  • [Journal Article] A sharp peak of the zero-temperature penetration depth at optimal composition in the iron-based superconductor BaFe2(As1-xPx)22012

    • Author(s)
      K. Hashimoto, K. Cho, T. Shibauchi, S. Kasahara, Y. Mizukami, R. Katsumata, Y. Tsuruhara, T. Terashima, H. Ikeda, M. A. Tanatar, H. Kitano, N. Salovich, R. W. Giannetta, P. Walmsley, A. Carrington, R. Prozorov, and Y. Matsuda
    • Journal Title

      Science

      Volume: 336 Pages: 1554-1557

    • DOI

      DOI:10.1126/science.1219821

    • Peer Reviewed
  • [Journal Article] Electronic nematicity above the structural and superconducting transition in BaFe2(As1-xPx)22012

    • Author(s)
      S. Kasahara, H. J. Shi, K. Hashimoto, S. Tonegawa, Y. Mizukami, T. Shibauchi, K. Sugimoto, T. Fukuda, T. Terashima, A. H. Nevidomskyy, and Y. Matsuda
    • Journal Title

      Nature

      Volume: 486 Pages: 382-385

    • DOI

      DOI:10.1038/nature11178

    • Peer Reviewed
  • [Journal Article] Emergent Rank-5 `Nematic' Order in URu2Si22012

    • Author(s)
      H. Ikeda, M.-T. Suzuki, R. Arita, T. Takimoto, T. Shibauchi, and Y. Matsuda
    • Journal Title

      Nature Physics

      Volume: 8 Pages: 528-533

    • DOI

      doi:10.1038/nphys2330

    • Peer Reviewed
  • [Journal Article] de Haas-van Alphen Study of the Fermi Surfaces of Superconducting LiFeP and LiFeAs2012

    • Author(s)
      C. Putzke
    • Journal Title

      Phys. Rev. Lett.

      Volume: 108 Pages: 047002-1-5

    • DOI

      10.1103/PhysRevLett.108.047002

    • Peer Reviewed
  • [Journal Article] Nodal versus Nodeless Behaviors of the Order Parameters of LiFeP and LiFeAs Superconductors from Magnetic Penetration-Depth Measurements2012

    • Author(s)
      K. Hashimoto
    • Journal Title

      Phys. Rev. Lett.

      Volume: 108 Pages: 047003-1-5

    • DOI

      10.1103/PhysRevLett.108.047003

    • Peer Reviewed
  • [Journal Article] Microscopic Evidence of Direct Coupling between Magnetic and Superconducting Order Parameters in BaFe2(As1-xPx)22012

    • Author(s)
      T. Iye
    • Journal Title

      J. Phys. Soc. Jpn.

      Volume: 81 Pages: 033701-1-4

    • DOI

      10.1143/JPSJ.81.033701

    • Peer Reviewed
  • [Journal Article] Contrasts in electron correlations and inelastic scattering between LiFeP and LiFeAs revealed by charge transport2012

    • Author(s)
      S. Kasahara
    • Journal Title

      Phys. Rev. B

      Volume: 85 Pages: 060503(R)-1-5

    • DOI

      10.1103/PhysRevB.85.060503

    • Peer Reviewed
  • [Journal Article] Gradual suppression of antiferromagnetism in BaFe2(As1-xPx)2: Zero-temperature evidence for a quantum critical point2012

    • Author(s)
      T. Iye
    • Journal Title

      Phys. Rev. B

      Volume: 85 Pages: 184505-1-5

    • DOI

      10.1103/PhysRevB.85.184505

    • Peer Reviewed
  • [Journal Article] Infrared Measurement of the Pseudogap of P-Doped and Co-Doped High-Temperature BaFe2As2 Superconductors2012

    • Author(s)
      S. J. Moon
    • Journal Title

      Phys. Rev. Lett.

      Volume: 109 Pages: 027006-1-6

    • DOI

      10.1103/PhysRevLett.109.027006

    • Peer Reviewed
  • [Journal Article] Cyclotron Resonance in the Hidden-Order Phase of URu2Si22012

    • Author(s)
      S. Tonegawa
    • Journal Title

      Phys. Rev. Lett.

      Volume: 109 Pages: 036401-1-6

    • DOI

      10.1103/PhysRevLett.109.036401

    • Peer Reviewed
  • [Journal Article] Octet-Line Node Structure of Superconducting Order Parameter in KFe2As22012

    • Author(s)
      K. Okazaki
    • Journal Title

      Science

      Volume: 337 Pages: 1314-1317

    • DOI

      10.1126/science.1222793

  • [Journal Article] Thermodynamic phase diagram, phase competition, and uniaxial pressure effects in BaFe2(As1-xPx)2 studied by thermal expansion2012

    • Author(s)
      A. E. Bohmer
    • Journal Title

      Phys. Rev. B

      Volume: 86 Pages: 094521-1-8

    • DOI

      10.1103/PhysRevB.86.094521

    • Peer Reviewed
  • [Journal Article] Novel Pauli-paramagnetic quantum phase in a Mott insulator2012

    • Author(s)
      D. Watanabe
    • Journal Title

      Nature Commun.

      Volume: 3 Pages: 1090-1-6

    • DOI

      10.1038/ncomms2082

    • Peer Reviewed
  • [Journal Article] Anomalous upper critical field in CeCoIn5/YbCoIn5 superlattices with a Rashba-type heavy fermion interface2012

    • Author(s)
      S. K. Goh
    • Journal Title

      Phys. Rev. Lett.

      Volume: 109 Pages: 157006-1-5

    • DOI

      10.1103/PhysRevLett.109.157006

    • Peer Reviewed
  • [Journal Article] Strong suppression of superconductivity by divalent ytterbium Kondo holes in CeCoIn52012

    • Author(s)
      M. Shimozawa
    • Journal Title

      Phys. Rev. B

      Volume: 86 Pages: 144526-1-5

    • DOI

      10.1103/PhysRevB.86.144526

    • Peer Reviewed
  • [Presentation] Quantum spin liquid2013

    • Author(s)
      Yuji Matsuda
    • Organizer
      3rd Japan-Israel Binational Workshop on Quantum Phenomena
    • Place of Presentation
      Okinawa, Japan
    • Year and Date
      20130311-20130313
    • Invited
  • [Presentation] Two dimensional confinement of heavy fermion in artificial superlattices2013

    • Author(s)
      Yuji Matsuda
    • Organizer
      REIMEI-Workshop: Heavy fermion superconductivity explored by anisotropic magnetic fluctuations in actinide compounds
    • Place of Presentation
      Tokyo, Japan
    • Year and Date
      20130218-20130219
    • Invited
  • [Presentation] Superconducting gap structure, hidden quantum criticality and nematic transition in BaFe2(As1-xPx)22013

    • Author(s)
      Yuji Matsuda
    • Organizer
      Bristol-Kyoto symposium
    • Place of Presentation
      Bristol, UK
    • Year and Date
      20130109-20130113
    • Invited
  • [Presentation] Novel Pauli paramagntic quantum phase in a Mott insulator2012

    • Author(s)
      Yuji Matsuda
    • Organizer
      Exotic Phases of Frustrated Magnets conference
    • Place of Presentation
      Santa Barbara, CA, USA
    • Year and Date
      20121008-20121012
    • Invited
  • [Presentation] Two dimensional confinement of heavy fermion in artificial superlattices2012

    • Author(s)
      Yuji Matsuda
    • Organizer
      Materials and Mechanism of Superconductivity
    • Place of Presentation
      Washington,D.C., USA
    • Year and Date
      20120729-20120803
    • Invited
  • [Presentation] Nematic transition and quantum critical point in iron-pnictide superconductors2012

    • Author(s)
      Yuji Matsuda
    • Organizer
      Japanese-German Symposium
    • Place of Presentation
      Izu, Japan
    • Year and Date
      20120714-20120717
  • [Presentation] Quantum criticality and electronic nematic phase in iron-pnictides2012

    • Author(s)
      Yuji Matsuda
    • Organizer
      The 19th International Conference on Magnetism (ICM) with Strongly Correlated Electron Systems
    • Place of Presentation
      Pusan, Korea
    • Year and Date
      20120708-20120713
    • Invited
  • [Presentation] Novel Pauli-paramagnetic quantum phase in a Mott insulator2012

    • Author(s)
      Yuji Matsuda
    • Organizer
      International Workshop Itinerant spin-orbital systems: from magnetic frustration to novel superconductivity
    • Place of Presentation
      Dresden, Germany
    • Year and Date
      20120520-20120525
    • Invited
  • [Presentation] Superconducting gap structure of iron-pnictide superconductors2012

    • Author(s)
      Yuji Matsuda
    • Organizer
      International Conference on Superconductivity and Magnetism
    • Place of Presentation
      Pusan, Korea
    • Year and Date
      20120429-20120504
    • Invited
  • [Book] 超伝導現象と高温超伝導2013

    • Author(s)
      松田祐司
    • Total Pages
      490-501
    • Publisher
      NTS出版

URL: 

Published: 2014-07-24  

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