VOLTAGE-FLUX BISTABILITY IN DAMPED DIRECT-CURRENT SQUIDS

We present an analysis and numerical study of a de superconducting qua ntum interference device (SQUID) with a damped loop inductance. We fin d a previously unreported regime of voltage-flux bistability due to th e damping resistor when the SQUID is biased below the zero-field criti cal current. We determine the region where this phenomenon can be foun d in the parameter space defined by the damping resistance and the ind uctance parameter. We show that switching between the bistable states can be controlled by external flux pulses and by adding thermal noise to the model, we have determined the maximum noise level at which the bistability can:be seen. (C) 1996 American Institute of Physics.