Superconducting YBa2Cu3O7-x based edge junctions with Y0.1Ca0.3Ba2Cu3O7-x barriers
ABSTRACT High-temperature superconductor YBa2cU3O7-x (YBCO) Josephson junctions were fabricated in an edge junction geometry using Y0.7Ca0.3Ba2O7-x as a barrier material. The films were deposited by pulsed-laser deposition and patterned by argon ion milling. The edge morphology of the bottom electrode after ion milling was investigated by atomic force microscopy. The yield of devices in terms of supercurrent continuity is nearly 100%. Critical current densities exceeding 106 A/cm2 at 75 K were obtained through crossovers of YBCO/YBCO under our processing conditions. Resistively shunted junction current-voltage characteristics and microwave-induced Shapiro steps were observed in a wide temperature range from 75 K to 84 K for the junctions.