AC susceptibility studies of grain-aligned superconductors by grained Bean model

AC susceptibility of low-Tc metallic superconductors shows smooth transition in the in-phase ?' and a peak in the out-phase ?. High-Tc oxide superconductors with anisotropic and grain-textured structures show deformed complex characteristics, such as double peaks in ? and shoulders in ?'. Instead of simple Bean model, a grained Bean model, where the superconducting grains is immersed in weak superconducting matrix, are proposed. The susceptibilities numerically analyzed using the grained Bean model show varied and deformed curves as observed in the high-Tc superconductors. From the dependence of ?' and ? on temperatures T and DC magnetic fields Bdc in grain-aligned Hg(Re)-1223 superconductors, textures of grains and interconnecting links and their grain-aligned nature can be estimated.