DISCRETE MODELS OF ABRIKOSOV VORTEX FLOW TRANSISTORS

Electronic devices based on flux flow phenomena in oxide superconducto rs have been under development, and are potentially important for appl ications, particularly in the interface between RSFQ circuits and sili con based room temperature electronics. Models for these flux flow tra nsistors (FFT's) usually have been based on discrete Josephson element s, ignoring the physics of fluxoid nucleation. We have explored a nume rical simulation of flux flow, also using discrete Josephson elements, but at the level of the Abrikosov vortex, so that nucleation at the f ilm edge becomes part of the model. Our results imply that the inhomog eneous coupling of the magnetic control is important for a saturated t ransfer function, rather than a periodic one, and that there is no adv antage in putting flux flow strips in parallel, separated by open gaps . Furthermore, gain may be increased by arranging the bias to separate ly optimize nucleation and transfer to the load.