AC susceptibility study in the single-phase Bi-2223 system

We have found that the composition, Bi1.2Pb0.33Sr1.54Ca2.06Cu3Oy which is comparatively poorer in Bi and Sr with respect to 2: 2: 2: 3, a single-phase 110 K superconductor can be obtained. Such polycrystalline samples have been synthesized by two different methods. The synthesized samples have been characterized by their X-ray diffraction patterns and temperature dependence of DC electrical resistivity and AC susceptibility down to 20K have been carried out. The samples have been identified as having single phase with a sharp transition. The results of their AC susceptibility have been analysed using Clem's critical state model. The effective volume fraction of the grains and the temperature dependence of the intergranular current density have been estimated.