Properties of multilevel ramp edge junctions and SQUIDs with laser-ablated SrTiO/sub 3/ barriers

We have fabricated junctions and DC SQUIDs using laser ablation for both the YBCO electrodes and the thin SrTiO/sub 3/ (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 (/spl sim/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 /spl mu//spl Phi//sub 0///spl radic/Hz and a 1/f upturn at about 0.2 Hz.<
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