The critical current density in type-II superconducting bulk materials

摘要: The critical current density Jc in type-II conventional and high-Tc superconducting bulk materials is investigated based on the quantum theory for vortex dynamics. It shown that a constant magnetic field, decreases weakly with increasing temperature when T T_f,Jc decays exponentially; while temperature, first decreases, then increases after reaching maximum, finally again as field increases. These results are agreement experiments.