Transport characteristics and flux dynamics in high T/sub c/ superconductors under the influence of pin fluctuation

Flux dynamics in a random pin medium have been studied with the Monte-Carlo method. It has been shown that flux depinning occurs percolatively in the disordered system and the scaling of electric field, E, vs. current density, J, curves reflect the stochastic property of the pin fluctuation. The analytical expressions for temperature and magnetic field dependent E-J curves have also been derived. The analytical expressions agreed quantitatively with the simulation and the in a Y/sub 1/Ba/sub 2/Cu/sub 3/O/sub 7-/spl delta// thin film at various temperature and magnetic field. Moreover, combining the analytical E-J relationship with Maxwell´s equations, we estimated the internal current distribution for alternating bias currents.