Studies of Vortex States in Anisotropic Superconductors by Low Temperature Scanning Spectroscopy and Muon Spin Rotation
| Project/Area Number |
14204035
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
固体物性Ⅱ(磁性・金属・低温)
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| Research Institution | Tokyo Institute of Technology |
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Principal Investigator |
NISHIDA Nobuhiko Tokyo Institute of Technology, Dept.of Physics, Professor, 大学院・理工学研究科, 教授 (50126140)
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| 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)
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| Project Period (FY) |
2002 – 2004
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| Project Status |
Completed (Fiscal Year 2004)
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| Budget Amount *help |
¥48,230,000 (Direct Cost: ¥37,100,000、Indirect Cost: ¥11,130,000)
Fiscal Year 2004: ¥4,160,000 (Direct Cost: ¥3,200,000、Indirect Cost: ¥960,000)
Fiscal Year 2003: ¥5,200,000 (Direct Cost: ¥4,000,000、Indirect Cost: ¥1,200,000)
Fiscal Year 2002: ¥38,870,000 (Direct Cost: ¥29,900,000、Indirect Cost: ¥8,970,000)
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| Keywords | scanning 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 / 実空間測定 / 超伝導準粒子状態密度 / ミュオンスピン回転 / 渦糸格子 / ミュオンスピン回転・緩和法 / 渦糸グラス / ミュオンスピン回転法 / 渦糸格子バンド / CeCoIn_5 |
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| 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.
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Report
(4 results)
Research Products
(17 results)
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[Publications] Y.Aoki, A.Tsuchiya, T.Kanayama, S.R.Saha, H.Sugawara, H.Sato, W.Higemoto, A.Koda, K.Oishi, K.Nishiyama, R.Kadono: "Time-reversal Symmetry-breaking Superconductivity n Heavy-Fermion PrOs4Sb12 detected bu Muon-Spin Relaxation"Phys.Rev.Lett.. 91. 067003-1-067003-4 (2003)
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