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2004 Fiscal Year Final Research Report Summary

Studies of Vortex States in Anisotropic Superconductors by Low Temperature Scanning Spectroscopy and Muon Spin Rotation

Research Project

Project/Area Number 14204035
Research Category

Grant-in-Aid for Scientific Research (A)

Allocation TypeSingle-year Grants
Section一般
Research Field 固体物性Ⅱ(磁性・金属・低温)
Research InstitutionTokyo Institute of Technology

Principal Investigator

NISHIDA Nobuhiko  Tokyo Institute of Technology, Dept.of Physics, Professor, 大学院・理工学研究科, 教授 (50126140)

Co-Investigator(Kenkyū-buntansha) KANEKO Shin-ichi  Tokyo Institute of Technology, Dept.of Physics, Research Associate, 大学院・理工学研究科, 助手 (40301171)
HIGEMOTO Wataru  Japan Atomic Energy Research, Researcher, 副主任研究員 (90291103)
Project Period (FY) 2002 – 2004
Keywordsscanning tunneling spectroscopy / anisotropic superconductor / vortex states / YNi_2B_2C / Bi_2Sr_2^CaCu_2O_x / real space measurements / quantum regime vortex / quasi-particle density of states
Research Abstract

We have developed low temperature high magnetic field scanning tunneling microscope (LT/HM-STM) and studied the vortex states of anise-tropic superconductors.
(1)Construction of LT/HM-STM : We have constructed two low temperature scanning tunneling microscopes : one is able to be operated in magnetic fields up to 15T at 4.2K and the other, combined with ^3He-^4He dilution refrigerator, I is able to be operated at temperatures down to 0.16K in 6T. We have found that S/N ration of scanning tunneling spectroscopy bu using dilution-refrigerator STM can be greatly improved by modifying the cooling method of the 1.5K stage ; this will help the improvement of LT-STM in the future.
(2)Scanning tunneling spectroscopy of vortex states of anisotropic superconductors in real time and space : The vortex states of YNi2B2C have been studied by Lt-STS/STM at 0.46K. The bound states of the vortex in YNi2B2C have been found by measuring the local density of states of quasi-particles by LT-STS/STM at 0.46K : the fourfold symmetric star-shaped and quantum-regime vortex core have been observed for the first time. This will a breakthrough to microscopic understanding of the vortex states in type-II superconductors. The collective creep of vortices has been successfully observed at temperatures from 6K down to 0.46K in 1T. This is the first visualization of the vortex movement below 1K. Vortex motion in high^temperature superconductors Bi2Sr2CaCu2Ox in 6T at 4.2K was also observed in real time and space. These will open a frontier of research of vortex dynamics including pinning effects in type-II superconductors. By using muon spin rotation anad relaxation method, we ha ve found that the superconducting state of PrOs4Sb12 is time-reversal symmetry breaking. The vortex states of PrOs4b12 have been studied by LT-STS at 0.46K and the results are now in analysis.

  • Research Products

    (9 results)

All 2005 2004 2003

All Journal Article (9 results)

  • [Journal Article] 四回対称性をもつYNi_2B_2C超伝導渦糸芯2005

    • Author(s)
      西森独志
    • Journal Title

      固体物理 40

      Pages: 363-369

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] First Observation of the Fourfold-symmetric and Quantum Regime Vortex Core in YNi2B2C by Scanning Tunneling Microscopy and Spectroscopy2004

    • Author(s)
      H.Nishimori
    • Journal Title

      J.Phys.Soc.Jpn. 73

      Pages: 3247-3250

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] First Observation of the Four fold-symmetric and Quantum Regime Vortex Core in YNi2B2C by Scanning Tunneling Microscopy and Spectroscopy2004

    • Author(s)
      H.Nishimori
    • Journal Title

      J.phys.Soc.Jpn. 73

      Pages: 3247-3250

    • Description
      「研究成果報告書概要(欧文)」より
  • [Journal Article] Ordered Vortex Lattice and Intrinsic Vortex Core States in Bi2Sr2CaCu2Ox studied by Scanning Microcopy and Spectroscopy2003

    • Author(s)
      Ken Matsuba
    • Journal Title

      J.Phys.Soc.Jpn. 72

      Pages: 2153-2156

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] Influence of disorder on superconductivity in Bi2Sr2CaCu22Ox studied by low temperature scanning tunneling spectroscopy2003

    • Author(s)
      Ken Matsuba
    • Journal Title

      Physica C 388-389

      Pages: 281-282

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] Time-Reversal Symmetry-Breaking Superconductivity in Heavy-Fermion PrOs_4Sb_<12> detected by Muon-Spin Relaxation2003

    • Author(s)
      Y.Aoki
    • Journal Title

      Phys.Rev.Lett. 91

      Pages: 067003-1-067003-4

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] 高温超伝導体Bi2Sr2CaCu2Oxにおける乱れと超伝導-STM渦糸測定を中心として2003

    • Author(s)
      松葉健
    • Journal Title

      固体物理 38

      Pages: 553-560

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] Influence of disorder on superconductivity in Bi2Sr2CaCu220x studied by low temperature scanning tunneling spectroscopy2003

    • Author(s)
      K.Matsuba
    • Journal Title

      Physica C 388-389

      Pages: 281-282

    • Description
      「研究成果報告書概要(欧文)」より
  • [Journal Article] Ordered Vortex Lattice and Intrinsic Vortex Core States in Bi2Sr2CaCu20x Studied by Scanning Tunneling Microscopy and Spectroscopy2003

    • Author(s)
      K.Matsuba
    • Journal Title

      J.phys.Soc.Jpn. 71

      Pages: 2153-2156

    • Description
      「研究成果報告書概要(欧文)」より

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Published: 2006-07-11  

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