HIGH-PERFORMANCE (HG,RE)BA2CACU2OY GRAIN-BOUNDARY JOSEPHSON-JUNCTIONSAND DC SUPERCONDUCTING QUANTUM INTERFERENCE DEVICES

High-performance grain-boundary Josephson junctions and de superconduc ting quantum interference devices (SQUIDs) have been fabricated using c-axis oriented (Hg, Re)Ba2CaCu2Oy thin films grown on bicrystal SrTiO 3 substrates with a 24 degrees misorientation angle. The junctions exh ibit supercurrent up to a temperature close to the film T-c and resist ively shunted junctionlike current-voltage characteristics. A rather h igh IcRn product of 400-460 mu V is observed at 77 K in some junctions . The de SQUIDs show a field-induced periodic voltage up to 111 K. The y also exhibit a voltage modulation depth as large as 90, 27, and 1-2 mu V at 77, 97, and 111 K, respectively. (C) 1998 American Institute o f Physics.