HIGH-TEMPERATURE SUPERCONDUCTING JOSEPHSON-JUNCTIONS IN A STACKED BICRYSTAL GEOMETRY

Bicrystal grain boundary Josephson junctions were fabricated in a stac k of two layers of YBa2Cu3Ox separated by epitaxial SrTiO3. Weak link behavior was observed in the bridges formed in both layers that had si milar shunted-junction characteristics but significantly different cri tical currents. Characteristic voltages up to 1.9 mV were measured at 4.5 K. The resonant structure was seen in the current-voltage characte ristics of the upper-layer junctions, and interactions between junctio ns in the two layers were evident. (C) 1997 American Institute of Phys ics.