超伝導電磁特性の数値解析 : 磁化と交流帯磁率(電気工学科)

Abstract

In-phase x'_n and out-phase x"_n components of n-th harmonic components of AC susceptibility under measuring parameters of a DC magnetic field B_<dc>, an amplitude B_a and a frequency f of the superimposed AC magnetic fields give a substantial information of the superconducting characteristics. In low-T_c metallic superconductors, x'_1 and x"_1 show a smooth transition and single peak. High-T_c oxide superconductors with anisotropic and grainy structures show a deformed complex characteristics. After introducing the theoretical deviation by a simple Bean model, AC susceptibilities are numerically analyzed using the γ-model developed by Irie and Yamafuji which gave a fine description of magnetic field distribution in the superconductor. It shows a more clear insight of the dependence of susceptibilities on the DC magnetic field and the pinning parameters.