| Project/Area Number |
09440127
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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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 | The University of Tokyo |
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Principal Investigator |
MATSUDA Yuji The University of Tokyo, Institute for Solid State Physics, Associate Professor, 物性研究所, 助教授 (50199816)
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| Co-Investigator(Kenkyū-buntansha) |
FURUKAWA Yuji Hokkaido University, Department of Physics, Research Associate, 大学院・理学研究科, 助手 (50280863)
KUMAGAI Ken-ichi Hokkaido University, Department of Physics, Professor, 大学院・理学研究科, 教授 (70029560)
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| Project Period (FY) |
1997 – 1998
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| Project Status |
Completed (Fiscal Year 1998)
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| Budget Amount *help |
¥9,400,000 (Direct Cost: ¥9,400,000)
Fiscal Year 1998: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 1997: ¥8,400,000 (Direct Cost: ¥8,400,000)
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| Keywords | Josephson effect / Plasma oscillation / Vortex lattice melting / Superconductivity / Vortex state / Columnar defect / 高温超伝導体 / BCS理論 / 重イオン照射 / 渦糸状態 / 有機超伝導体 / ジョセフソンプラズマ / 過糸格子 / 過糸液体 / コラムナ-欠陥 |
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| Research Abstract |
Josephson plasma resonance is a powerful means to probe the vortex state of layered superconductors, enabling us to determine the interlayer Josephson coupling quantitatively. In this research projest, we have measured how the Josephson coupling changes when the vortex lattice melts into the liquid in highly anisotropic Bi_2Sr_2CaCu_2O_<8+8>. We showed that the Josephson coupling strength changes dramatically when going accross the melting line. This result shows that the vortex lattice undergoes the transition from the three dimentional lattice to the decoupled pancake gas. We also studied the effect of the heavy-ion-irradiation. We showed that the introduction of the columnar defects changes the Josephson coupling dramatically. The coupling transition in which the decoupled pancakes couple with magnetic field. This transition occurs almost one-third of the matching field. We calculated the correlation length of the pancekes along the c-axis quantitatively from the detailed analysis of the resonance.
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