THE HYSTERESIS OF MAGNETIZATION IN THE GENERALIZED CRITICAL-STATE MODEL - LOW-FIELD APPROXIMATION

The generalized critical-state model is extended to the low-field case by a new low-field approximation. We calculate the hysteresis loops o f magnetization for H(max) < H and H(max) > H*. We obtain new behavio rs of M(H) which are different from the results derived from the Bean and Kim models. Our theory qualitatively agrees with the experimental results for high-T(c) superconductors. Some important macroscopic para meters may be obtained by fitting our theory with the experimental dat a.