Flux creep with logarithmic U(j) dependence

In this paper we studied the flux motion in a high-Tc superconductor. For both field-cooled and zero-field-cooled cases, we numerically solved the flux motion equations and calculated various magnetizations M(t) changing with time t. The scaling behavior of the magnetization is obtained. There is a kink in the magnetization curve that corresponds to the flux front reaching the middle of the slab sample. The self-organized critical state (SOC) is related to the early time of the flux penetration and the effect of temperature on the SOC is discussed