MICROWAVE-INDUCED DC VOLTAGES IN BAPB1-XBIXO3 BICRYSTAL JOSEPHSON-JUNCTIONS

We have fabricated an artificial BaPb1-xBixO3 grain boundary tunnel ju nction on a SrTiO3 bicrystal substrate. Current-voltage characteristic s exhibit supercurrent and quasi-particle tunneling which is commonly observed for superconductor-insulator-superconductor (SIS) type juncti ons. A Shapiro step is observed for a junction with a large area under microwave radiation. On the other hand, microwave-induced de voltages at zero bias current are observed for a narrow junction. This depende nce on the junction width indicates that generation of the microwave-i nduced voltages is related to normal resistance or capacitance of a ju nction.