HIGH-T-C, SUPERCONDUCTOR NORMAL-METAL/SUPERCONDUCTOR EDGE JUNCTIONS AND SQUIDS WITH INTEGRATED GROUNDPLANES/

Epitaxial, high-T-c superconductor/normal-metal/superconductor (SNS) e dge-geometry weak links and superconducting quantum interference devic es (SQUIDs) have been fabricated with integrated YBa2Cu3O7 (YBCO) grou ndplanes and SrTiO3 insulators, using a process which incorporates six epitaxial layers. The SNS edge junctions were produced using off-axis sputtered films and Co-doped-YBCO normal metal interlayers. These dev ices show excellent performance with typical critical current-resistan ce (I(c)R(n)) products of 500-800 mu V for 100-150 Angstrom thick norm al metal layers at 65 K, and 1-sigma critical current density (J(c)) s preads as small as 12%. SNS SQUIDs incorporating groundplanes exhibit voltage modulation of up to 130 mu V at 65 K and 40 mu V at 77 K. SQUI D inductance measurements indicate microstrip inductance values of 1 p H per square at 65 K. (C) 1996 American Institute of Physics.