PROPERTIES OF MULTILEVEL RAMP EDGE JUNCTIONS AND SQUIDS WITH LASER-ABLATED SRTIO3 BARRIERS

We have fabricated junctions and DC SQUIDs using laser ablation for both the YBCO electrodes and the thin SrTiO3 (STO) barrier regions in a! variety of device configurations. These SQUIDs operate reliably at 77 K and preliminary results on a limited number of devices show that they store reasonably well for periods in excess of one year, and exhibit only small changes with repeated cycles (similar to 10) between room temperature and 77 K. Noise measurements made using bias reversing on a SQUID (92 pH) at 77 K give a white noise of about 15 mu Phi(0)/root Hz and a 1/f upturn at about 0.2 Hz.