Critical currents in superconductor-normal metal-superconductor junctions

Critical currents in superconductor-normal metal-superconductor junctions in a parallel magnetic field are studied theoretically. It is found that the supercurrent amplitude can be strongly suppressed by the magnetic field, due to the rapid field-dependent decay of the pair condensation amplitude inside the normal barrier. For a thick normal layer, and/or for high fields, an exponential decay of the critical current with increasing field is obtained. (author)