PHYSICS OF HIGH-T-C JOSEPHSON-JUNCTIONS AND SQUIDS

Effects of magnetic fields and microwave radiation on I-V characterist ics of YBa2Cu3Oy high-T-c Josephson junctions, SQUIDs and Josephson ar rays were reported in this experiment, with special emphasis focused o n the effects of microwave radiation. In addition to the ordinary cons tant-voltage steps resulting from the ac Josephson effect, noninteger constant voltage steps are occasionally observed under microwave radia tion. We attribute these noninteger constant-voltage steps to the flux coupled to junctions or SQUIDs. Resistive SQUIDs disclose V - Phi mod ulation without a biased current. The peak to peak value Delta V of a V - Phi curve is enhanced by microwave radiation.