PROXIMITY-COUPLED WEAK LINKS IN YBCO FILMS

We report measurements on S-N-S planar microbridges made from high-quality in situ sputtered YBCO films. The devices were fabricated using single superconducting films with a patterned gap bridged by sputter-deposited silver. A number of devices exhibit supercurrents as well as microwave-induced steps in the current-voltage characteristics. In the best devices the normal state resistance is consistent with expected values. We discuss the consequences of the anisotropy of YBCO as well as the effects of various fabrication techniques on device performance and yield.