Effect of Lower Critical Fields on Magnetization of a Single-Crystal Bi2Sr2CaCu2O8+d Bulk Superconductor (特集 酸化物超伝導体の合成と特性) Effect of Lower Critical Fields on Magnetization of a Single-Crystal Bi_2Sr_2CaCu_2O_<8+d> Bulk Superconductor
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To test the utility of the modified Kim-Anderson critical-state model for study of the magnetic response of ceramic superconductors, we measured the initial magnetization, hysteresis loops and ac complex susceptibilities X<SUB>n</SUB>=X'<SUB>n</SUB>-iX"<SUB>n</SUB>(n =1, 2, 3, 5) of a single-crystal Bi<SUB>2</SUB>Sr<SUB>2</SUB>CaCu<SUB>2</SUB>O<SUB>8+d</SUB> bulk sample. The results were simulated in the framework of the model. Analyses of Xn have shown that generation of the higher harmonics can be qualitatively reproduced, where the material parameters k and B<SUB>0</SUB>, surface barriers ΔH and lower critical fields Hcl, involved were used as fitting parameters. Comparison of the observed data with the calculated results has revealed that nonzero values of H<SUB>cl</SUB>, play an essential role in the magnetic characteristics of the sample.
- J. Jpn. Soc. Powder Powder Metallurgy
J. Jpn. Soc. Powder Powder Metallurgy 45(2), 135-139, 1998-02-15
Japan Society of Powder and Powder Metallurgy