Step phenomenon of vortices flow in superconductor

We investigate numerically the transport of vortices in superconductors under a driving force by using Langevin dynamics. The velocity-driving force characteristic (Vx–FL curve) of superconductors includes a region with series of stages. The impact of the initial states was investigated and there is a dramatic difference between the initial state produced by the current annealing process (CAP) and the well pinned state (WPS).