Characterization of high-Tc superconductors using the higher-harmonic susceptibility

The harmonic magnetic susceptibilities of high-Tc superconductors are examined and corresponding harmonic susceptibilities are calculated employing a model by Kim and coworkers. According to Kim's model, Jc is a function of the internal magnetic field Hi, Jc(H) = k/(Ho + |Hi|) where k and Ho are constants. In the model calculations, full penetrations field, Hp, is taken to be Ho[(1 + p2)1/2-1] where p = (2ka)1/2/Ho. As a result of the comparison of model calculations with experiments, authors conclude that the harmonic susceptibilities for lower p values (p < 10) correspond to the similar characteristic magnetic behavior of granular superconductors, while the harmonic susceptibilities for higher p values correspond to the behavior of homogeneous superconductors such as single crystal or samples with contiguous oriented grains. 12 refs.