HYSTERETIC JOSEPHSON-JUNCTION BEHAVIOR AND PHASE DIFFUSION IN BA1-XKXBIO3 FILMS

In Ba1-xKxBiO3 multidomain films grown on LaAlO3 substrates we find evidence for hysteretic Josephson-junction behavior. The junctions exhibit critical currents of a few muA and a finite zero-bias resistance. The critical current and zero-bias resistance depend on temperature, and amplitude of external rf irradiation. Qualitative features of the measured I-V curves can be accounted for by a simple model based on junctions in series coupled by a shunt capacitance. Estimates of the junction parameters are obtained by quantitative comparison of the data with an extended model based on classical phase diffusion.