Simulation on local flux creep in non-ideal type-II superconductors: The effect of non-uniform pinning potential and surface potential

Based on the thermally activated model,the flux creep process in the case o f non-uniform pinning potential and surface pinning potential in nonideal t ype II superconductors is studied through computer simulation. Global and l ocal magnetization curves are calculated and the logarithmic time dependenc e of local magnetic induction under a constant external field is examined. The results show that the motion of the flux is much restrained in the non- uniform case and the flux line is easy to be captured by the strong pinning center. The surface potential has marked effect in preventing the flux fro m going into and leaving the sample. Compared with the global behavior,the local magnetization is much more sensitive to the non-uniform pinning poten tial and the magnetic field sweep rate.