AC susceptibility study in the 85 K phase of the Bi-Sr-Ca-Cu-O system

Abstract

The temperature variation of AC susceptibility at different AC field amplitudes has been measured on cylindrical samples of the 85 K phase of the Bi-Sr-Ca-Cu-O system. Three samples used in the present study were obtained from different starting compositions and by different preparation techniques. The susceptibility data have been analyzed in terms of Bean's and Kim's critical state models. The temperature dependence of the critical current density and the effective volume fraction of the grains were estimated. The press-sintered samples shows improvement in the critical current density and a stronger coupling between the grains. Moreover, our analysis shows that the press-sintered sample closely follows Bean's field-independent critical state model. © 1994.