| Project/Area Number |
63044096
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| Research Category |
Grant-in-Aid for international Scientific Research
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| Allocation Type | Single-year Grants |
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| Section | Joint Research |
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| Research Institution | Hiroshima University |
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Principal Investigator |
KOMURA Shigehiro Professor, Faculty of Integrated Arts and Sciences, Hiroshima University, 総合科学部, 教授 (50034583)
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| Co-Investigator(Kenkyū-buntansha) |
SPRINGER Tasso Group Director, Institut fur Festkorperforschung, Forschungszentrum Julich GmbH,, 固体物理研究所, 研究室長
SCHWAHN Dietmar Researcher, Institut fur Festkorperforschung, Forschungszentrum Julich GmbH, Fed, 固体物理研究所, 研究員
TAKEDA Takayoshi Associate Professor, Faculty of Integrated Arts and Sciences, Hiroshima Universi, 総合科学部, 助教授 (70034593)
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| Project Period (FY) |
1988 – 1990
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| Project Status |
Completed (Fiscal Year 1990)
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| Budget Amount *help |
¥5,700,000 (Direct Cost: ¥5,700,000)
Fiscal Year 1990: ¥1,900,000 (Direct Cost: ¥1,900,000)
Fiscal Year 1989: ¥1,900,000 (Direct Cost: ¥1,900,000)
Fiscal Year 1988: ¥1,900,000 (Direct Cost: ¥1,900,000)
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| Keywords | Small angle neutron scattering / Depolarization of transmitted neutrons / YBa_2Du_3O_7 / Magnetic flux-line lattice / Depinning of flux-line / Flux-creep / High-T_C superconductor |
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| Research Abstract |
For the first 2 years of this project we have applied a method of small angle neutron scattering and for the last 1 year another method of depolarization measurement of transmitted neutrons in order to study the magnetic flux-line lattice structures in superconducting oxides YBa_2Cu_3O_7 or Bi_2SrCaCu_2O_8.
In the first method after confirming that we can observe a Bragg peak from the magnetic tlux-line lattice structures in superconducting metal niobium, we tried to measure in similar experimental conditions a Bragg peak from those in superconducting oxides. However we failed to observe it, because the Landau-Ginzburg parameter kappais 100 for the oxides in comparison with that of 4 in niobium metal.
Then we changed to the second method in which we measured the depolarization of almost 100% polarized neutrons that were transmitted through the superconducting oxides. We found that the depolarization of neutrons was very much sensitive to the state of the magnetic flux-line lattice structures.
From this experiment we observed the dependence of the depolarization of neutrons on a change of the magnetic field applied to the samples, a change of the temperature of the samples and also an elapsed time at constant temperature after it was changed.
In conclusion, we have found that several experimental conditions must be fulfilled in order to measure a Bragg peak from the magnetic flux-line lattice structure in the superconducting oxides, and that the observation of the depolarization of polarized neutrons through the superconducting oxides provides a very sensible tool to examine and characterize the state of the magnetic flux-line lattice structures.
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