The Study on AC Susceptibility Grained Model for The High-Tc Superconductor Bi-2223

The magnetic properties and the current transport of High-T(c) ceramics are governed not only by the nature of diamagnetic grains but also by their interconnections which constitute the superconducting matrix. Such a sintered High-T(c) Superconductor has two effects. One is intrinsic to the superconducting grains and the other is characteristic of the coupling between grains These phenomena have been widely studied in order to understand the mechanisms governing the flux lines dynamic within critical-state models. While the original Bean model of the critical-state only predicts single characteristic in the imaginary part of the fundamental susceptibilities, grained Bean model, where the superconducting grains are immersed in weak superconducting matrix, predicts the typical double peak appear in the imaginary part and double transitions in the real part. The predictions of the grained Bean model for the field and temperature dependencies of the ac magnetic susceptibilities are compared with experimental results