BEHAVIOR OF HIGH-TC Y1BA2CU3OY SUPERCONDUCTING BRIDGES IN A MICROWAVE FIELD

The external microwave-field dependence of harmonic and subharmonic Shapiro steps and the microwave self-radiation due to the coherent motion of vortices in high-T(c) superconducting granular Y1Ba2Cu3Oy bridges are observed and compared with those of the Josephson Nb-Si-Nb edge-junctions in the centimeter-wave to millimeter-wave range. The harmonic and subharmonic steps of Y1Ba2Cu3Oy bridges are related to the synchronization between the applied microwave signal and the local super-current oscillations generated by the moving hypervortices in accordance with the Josephson condition V = (n/m) (h/2e)f The microwave-induced subharmonic steps (n = 1, 2 and m = 1, 2, 3) are discussed in connection with the coherent synchronizing motion of hypervortices in bridges.