Transport properties of Nb/yttria-stabilized-zirconia/Nb Josephson junctions

Nb/yttria-stabilized zirconia (YSZ)/Nb Josephson junctions have been fabricated. The YSZ interlayer resistivity was found to have values of /spl sim/1 m/spl Omega/ - m and has a weak temperature dependence. The current-voltage characteristics at temperatures from 4.2 K to values close to the Nb critical temperature of /spl sim/8.0 K have been studied. The junction critical current was found to have an exponential relationship with both the YSZ interlayer length and the temperature. These results are consistent with the predicted behavior of a superconductor-normal metal-superconductor junction due to the proximity effect.