3流体モデルによる低温超伝導体の表面インピーダンスの解釈に関する検討  [in Japanese] Some discussions of an interpretation of surface impedance of low-Tc superconductors by three-fluid model  [in Japanese]

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Abstract

3流体モデルは高温超伝導体のマイクロ波特性を現象論的に説明するのに有効であった。本モデルでは、従来の2流体モデルに残留電子密度n_<res>を考慮し、またそれら常伝導電子に運動量緩和時間τ温度依存性を導入している。本報告では低温超伝導体の表面インピーダンスの解釈においてもこの3流体モデルが有効であることが実証される。T_c=9.3KのNb薄膜のR_sの測定値に対して、このモデルによる計算結果がよく一致することを示す。さらにこのモデルでn_<res>を考慮しない、言い換えると2流体モデルにτの温度依存性のみを考慮した2流体モデルがBCS理論から予想されるマイクロ波特性とよく一致することを示す。

It is shown that a three-fluid model, which was successfully introduced to explain microwave characteristics of high-T_c superconductors phenomenologically, is valid also to explain ones for low-T_c superconductors. In this model, two contributions of a residual normal electron in addition to a super and a normal electron in the conventional two-fluid model and of temperature(T-) dependence of momentum relaxation time τfor both these normal electrons are taken into account. Measured results of T-dependence of the surface resistance R_s for a Nb film with T_c=9.3K agree very well with an R_s curve calculated by the present model. Furthermore an improved two-fluid model, which corresponds to the case of n_<res>=0 in the three-fluid model or to a two-fluid model with τ dependent of T, is shown to agree almost perfectly with microwave characteristics of low-T_c superconductors expected from the BCS theory.

Journal

  • Technical report of IEICE. SCE

    Technical report of IEICE. SCE 97(19), 71-76, 1997-04-23

    The Institute of Electronics, Information and Communication Engineers

References:  11

Codes

  • NII Article ID (NAID)
    110003187323
  • NII NACSIS-CAT ID (NCID)
    AN10012885
  • Text Lang
    JPN
  • Article Type
    ART
  • Data Source
    CJP  NII-ELS 
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