Y-Ba-Cu-O/Au/Nb ramp-type Josephson junctions

Ramp-type junctions connecting the d-wave superconductor YBa/sub 2/Cu/sub 3/O/sub 7-/spl delta// and the s-wave superconductor niobium are fabricated using a thin gold layer as a chemical barrier. High critical current densities exceeding 5 kA/cm/sup 2/ are obtained. The normal state resistivity (R/sub n/A) values of the junctions are of the order of 0.1 /spl mu//spl Omega/ cm/sup 2/. The magnetic field behavior of the critical current of junctions oriented in the [10l]- and in the [11l]-direction of the YBa/sub 2/Cu/sub 3/O/sub 7-/spl delta// is explained in terms of a predominant d(x/sup 2/-y/sup 2/) order parameter in the high-T/sub c/ superconductor.