Nonuniversal critical behavior in the critical current of superconducting composites

We report the results of numerical simulations of two-dimensional percolative networks of superconductors. Near the percolation threshold p/sub c/, the critical current density J/sub c/ of these networks varies as (p-p/sub c/)/sup v/, where p is the fraction of superconducting material present. The exponent v is found to be dependent on the microstructure of the network. Excellent agreement is obtained between our numerical values of v and predictions for v based on the nodes-links-blobs-necks model