YBa/sub 2/Cu/sub 3/O/sub 7/ step-edge RF SQUID biased at 10 GHz

The measurement of a YBa/sub 2/Cu/sub 3/O/sub 7/ (YBCO) step-edge RF SQUID is discussed. The step-edge technique permits high-yield fabrication of high-temperature superconducting (HTS) SQUIDs in high-quality epitaxial YBCO films. A comparison is made of measurements made at bias frequencies of 27 MHz and 10 GHz, the latter using a TE/sub 011/ copper cavity. Observed differences in the operation of the SQUID at these two frequencies are largely attributable to differences in the measurement configurations. The 10 GHz bias frequency may exceed the r/2 pi L characteristic frequency of the SQUID loop.