OPTIMIZING SNS JOSEPHSON-JUNCTIONS FOR HIGH CRITICAL CURRENT-DENSITY IN BISRCACUO-METAL COMPOSITES

The use of superconducting BiSrCaCuO (BiSCO) wires or tapes in electro nic devices implies the optimization of the transport properties in oh mic contacts between the superconductor and the ''normal'' metal in th e circuit. This paper presents results of theoretical calculations, ba sed on modifications of tunneling theory in SNS, in both the ''pure'' and ''dirty'' limits. The aim is to sort the relevant parameters for t he maximum current density. For a specific superconductor and a ''norm al'' metal, the critical current density has an optimum value, dependi ng on the ''normal'' metal resistivity in the ''dirty'' limit, and on the ratio of Fermi velocities in the ''pure'' limit.