We studied, both theoretically and experimentally, the ac magnetic response of type-II superconductors superimposed on a weak Hdc field. Theoretical simulations were made within the construct of the Kim-Anderson critical-state model, where the critical current density Jc is assumed to be given by Jc= k / (B0+|Bi|). k and B0 are temperature-dependent material parameters, and Bi is the local flux density in the sample. We also measured complex susceptibilities Xn=X′n-iX″n (n=1,2,3,5,7) of a melt-processed YBa2Cu3Oy specimen and analyzed the observed Xn by applying the magnetization equations derived from the Kim-Anderson model. We found that the experimental results were qualitatively well reproduced. Present results indicate that, for a specimen of which Jc sensitively varies with B1, the effect of a weak Hdc should be explicitly taken into consideration for studies of the ac magnetization.
|ジャーナル||Funtai Oyobi Fummatsu Yakin/Journal of the Japan Society of Powder and Powder Metallurgy|
|出版ステータス||Published - 1998 7月|
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