Tunneling between Superconductors in the Vortex State

Superconductor-insulator-superconductor (S-I-S) and S/sub 1/-I-S/sub 2/ tunne l junctions have been studied with the thin-film electrodes in a dilute vortex state, at temperatures such that the tunneling is predominantly due to the vortex-core excitations. We conclude that the vortex cores in the upper film lie on top of those in the lower film, but that the net tunneling transition probability between vortex-core states is very much smaller than usual tunneling probabilities. (auth)