Critical current enhancement due to an electric field in a granular d-wavesuperconductor

We study the effects of an electric field in the transport properties of bu lk granular superconductors with different kinds of disorders. We find that for a d-wave granular superconductor with random pi junctions the critical current always increases after applying a strong electric field, regardles s of the polarity of the field. This result plus a change in the voltage as a function of the electric field are in good agreement with experimental r esults in ceramic high T-c superconductors.