Dynamics of metastable vortex states in weakly pinned superconductors: A phenomenological model

We present a phenomenological model for the vortex dynamics in the peak effect region of weakly pinned superconductors. We explain the history dependent dynamic response of the metastable vortex states subjected to a transport current and the hysteretic voltage-current characteristics observed in the vicinity of peak effect in weakly pinned superconductors. A strong variation in voltage current characteristics with the current sweep rate and the anomalous dependence of critical current density $J_c$ on the magnetic field sweep rate have also been accounted for by this model.