CHARACTERIZATION OF RAMP EDGE-GEOMETRY AG-YBA2CU3O7-X PRBA2CU3O7-X/AG-YBA2CU3O7-X JUNCTIONS AND DC SQUIDS/

High-temperature superconducting Josephson junctions and dc SQUIDs wer e fabricated using a ramp edge-geometry SNS configuration. Ag-doped YB a2Cu3O7-x was used as electrodes and PrBa2Cu3O7-x as barrier. The IcRn value of the junctions was in excess of 120 mu V at 75 K, The dc SQUI Ds showed a flux modulation depth, partial derivative V/partial deriva tive Phi, over 150 mu V/Phi(0) at 75K. The flux noise of the devices, measured with de bias currents operated at 75 K, showed a 1/f dependen ce at low frequency having values below 100 mu Phi(0)Hz(-1/2) (the bes t values in the range of 30 similar to 40 mu Phi(0)Hz(-1/2)) at 1 Hz a nd less than 5 mu Phi(0)Hz(-1/2) in the white noise region. The voltag e modulation and magnetic field noise were 37 mu V and similar to 2 pT Hz(-1/2) at 1 kHz for the directly-coupled dc SQUID magnetometers (wit h a pick-up loop 6 mm x 3.5 mm) based on the ramp edge-geometry SNS co nfiguration.