PHASE COHERENCE IN THE HYSTERETIC MAGNETIC-BEHAVIOR OF PARALLEL JOSEPHSON-JUNCTION ARRAYS

We report on the hysteretic field-dependent critical currents of large inductance arrays with up to ten YBa2Cu3O7 grain-boundary junctions i n parallel. A peak in the critical current, roughly equal to its initi al zero-field value, is observed after each reversal of the field swee p. This behavior indicates that the junction phases become equal modul o 2pi (self-organized phase coherence) as the system relaxes away from the critical state. The primary features can be modeled using a Frenk el-Kontorova model generalized to include global interactions due to m utual inductance.