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1993 Fiscal Year Final Research Report Summary

Proximity effects and pinning properties in superconducting wires for ac use

Research Project

Project/Area Number 04650230
Research Category

Grant-in-Aid for General Scientific Research (C)

Allocation TypeSingle-year Grants
Research Field 電力工学
Research InstitutionTohoku University

Principal Investigator

SUZUKI Mitsumasa  Tohoku University, Graduate School of Information Sciences Associate Prof., 大学院・情報科学研究科, 助教授 (40091706)

Co-Investigator(Kenkyū-buntansha) TAKANAKA Kenji  Tohoku University, Dept. of Applied Physics, Prof., 工学部, 教授 (80005321)
Project Period (FY) 1992 – 1993
KeywordsMultifilamentary Superconducting Wire / Proximity Effect / Critical Temperature / Upper Critical Field / Critical Current Density / NbTi
Research Abstract

In order to get a sufficient knowledge of ac loss and critical current in superconducting wires for ac use, multifilamentary superconducting wires with various filament sizes and different matrixes are investigated on their transiton temperature T_c and upper critical field B_<c2> including its temperature dependence. Much attention has been directed to the effects of filament size and matrix material to T_c and B_<c2>. Experimental resultls were analyzed in the framework of the GLAG theory. Futher, a theroretical analysis of B_<c2> in superconducting superlattices which are similar to multilayr wires in structure, has been done. Obtained results are summarized as follows.
1. T_c : As the filament size df of samples is decreased from 1 mu m, T_c generally decreases from 9.35 to 7.84 K.A marked decrease in T_c appears around df=0.07 mu m and is ascribed to the proximity effect between the filament and surrounding matrix.
2. B_<c2> : Values of B_<c2> at 4.2 K also decrease with decreasing df. The GL parameter Kappa GL increases with decreasing df and ranges from 40 to 60. An increase in Kappa GL for finer filament samples may lighten the decrease in B_<c2>.
In superconducting superlattices where two layrs with different diffusion constants alternately pile up, values of B_<c2> parallel and perpendicular to the layr planes are appreciably different. In particular, the temperture dependence of B_<c2> parallel to the layr planes are expected to change at a temperature.

  • Research Products

    (14 results)

All Other

All Publications (14 results)

  • [Publications] 鈴木光政,三橋説: "NbTi極細多芯超伝導線の臨界電流密度とピンニング特性 I.熱処理線" 低温工学. 28-1. 22-29 (1993)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 鈴木光政,三橋説: "NbTi極細多芯超伝導線の臨界電流密度とピンニング特性 II.非熱処理線" 低温工学. 28-1. 30-39 (1993)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 鈴木光政,三橋説,舟山邦男: "超伝導臨界電流の温度特性測定用断熱セルの製作" 低温工学. 28-1. 56-60 (1993)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] M.Suzuki,S.Mitsuhashi: "Transition temperatures and upper critical fields in multifilamentary NbTi wires" Advanced in Cryogenic Engineering. 40. (1994)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] K.Takanaka: "Upper critical fields for superconducting superlattices" J.Phys.Soc.Jpn. 61. 2865-2976 (1992)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] K.Takanaka: "Surface effects on the critical field of superconducting superlattices" J.Magn.& Magn.Mater.126. 619-621 (1993)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] K.Takanaka,T.Nagashima: "Magnetic properties of superconducting uniaxial materials" Physica C. 218. 379-386 (1993)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] M.Suzuki, S.Mitsuhashi: "Critical Current Density and Pinning Behavior in Multifilamentary NbTi wires ; I.Heat-Treated Wires" J.Cryo. Soc. Jpn. 28-1. 22-29 (1993)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] M.Suzuki, S.Mitsuhashi: "Critical Current Density and Pinning Behavior in Multifilamentary NbTi wires ; II.Non-Heat-Treated Wires" J.Cryo. Soc. Jpn. 28-1. 30-39 (1993)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] M.Suzuki, S.Mitsuhashi, K.Funayama: "Variable Temperature Apparatus for the Measurement of Temperature Dependence of Superconducting Critical Current" J.Cryo. Soc. Jpn. 28-1. 56-60 (1993)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] M.Suzuki, S.Mitsuhashi: "Transition temperatures and upper critical fields in multifilamentary NbTi wires" Advanced in Cryo. Eng.40. (1994)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] K.Takanaka: "Upper critical fields for superconducting superlattices" J.Phys. Soc. Jpn. 61. 2865-2976 (1992)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] K.Takanaka: "Surface effects on the critical fields of superconducting superlattices" J.Magn. & Magn. Mater.126. 619-621 (1993)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] K.Takanaka, T.Nagashima: "Magnetic properties of superconducting uniaxial materials" Physica C. 218. 379-386 (1993)

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

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Published: 1995-03-27  

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