| Project/Area Number |
62540222
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
固体物性
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| Research Institution | Muroran Institute of Technology |
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Principal Investigator |
NAGATA Shoichi Muroran Inst. of Technology Dept. of Appl. Materials Sci. Associate Professor, 工学部, 助教授 (80155936)
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| Co-Investigator(Kenkyū-buntansha) |
SHIROTANI Ichimin Muroran Inst. of Technology Dept. of Electrical. Eng. Professor, 工学部, 教授 (90110692)
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| Project Period (FY) |
1987 – 1989
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| Project Status |
Completed (Fiscal Year 1989)
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| Budget Amount *help |
¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1989: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1988: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1987: ¥1,000,000 (Direct Cost: ¥1,000,000)
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| Keywords | TaSe_3 / Superconductivity / Quasi-one-dimensional Conductor / The Meissner Effect / SQUID / Diamagnetism / London Model / ヘリウム3クライオスタット / ヘリウム-3クライオスタット / 一次元伝導体 / マイスナー効果 / 臨界電流密度 / ロンドン方程式 / 超伝導量子干渉計 / 常伝導状態 / 低次元伝導体 / 一次元伝導 / ウムクラップ散乱 / 臨界電流 / 臨界磁場 |
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| Research Abstract |
THE MEISSNER EFFECT IN TaSe_3 The Meissner effect of the quasi-one-dimensional conductor TaSe_3 is studied using a SQUID magnetometer. Susceptibility x does not show any significant variation of diamagnetism, with magnetic fields parallel and perpendicular to crystalline b-axis over a low magnetic field range of 7.2 mOe to 4.0 Oe. The diamagnetism is quite weak and the value of chi is much less than -3.OX10^<-3> emu/cm^3. Furthermore, thd susceptibility chi does not exhibit any indication of an abrupt change at 2.1 K. A single whisker consists of many fibers where some fibers (very thin filament-like) become superconducting below 2.1 K.
Resistivity of TaSe_3 drops near zero below 2.1 K. Why is the Meissner effect suppressed quite strongly in TaSe_3 ? A basic origin of this small diamagnetism is discussed on the basis of numerical computer calculations for the London model.As a simplified model, the diamagnetic susceptibility chi for a infinite cylinder having radius, a , is calculated systematically as a function of a/lambda, here lambda is the London penetration depth. In TaSe_3, the superconducting region is strictly restricted to extremely thin filaments along the b-axis in the single whisker. Furthermore. these superconducting filaments are individually isolated above 0.40 K in the whisker. The radii of the filaments are much less than lambda ( at most a/lambda <less than or equal>0.30 ), then, the magnetic flux will penetrate uniformly.Consequently the Meissner effect is substantially smeared out.
It should be noted that our experimental results give the single whisker's intrinsic material property. Our results could totally differ from that of the large amount of massive specimens which are randomly oriented and are greatly interpenetrating.
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