EXPERIMENTAL-OBSERVATION OF TRANSITIONS B ETWEEN PHASE STATES IN 4-JUNCTION PARALLEL-SERIAL JOSEPHSON LOOPS

The experimental data suggesting the existence of stationary phase sta tes in multiple-junction interferometers, which are a consequence of t he ambiguous relation between the phases of strong and weak junctions of the loop, are obtained. The theoretical calculations hold that each state has its own specific dependence of critical current on external magnetic flux. The transitions between the phase states as regularly repeated jumps of voltage are observed.