Discrete models of Abrikosov vortex flow transistors

Electronic devices based on flux flow phenomena in oxide superconductors have been under development, and are potentially important for applications, particularly in the interface between RSFQ circuits and silicon based room temperature electronics. Models for these flux flow transistors (FFTs) usually have been based on discrete Josephson elements, ignoring the physics of fluxoid nucleation. We have explored a numerical simulation of flux flow also using discrete Josephson elements, but at the level of the Abrikosov vortex, so that nucleation at the film edge becomes part of the model. Our results imply that the inhomogeneous coupling of the magnetic control is important for a saturated transfer function, rather than a periodic one, and that there is no advantage in putting flux flow strips in parallel, separated by open gaps. Furthermore, gain may be increased by arranging the bias to separately optimize nucleation and transfer to the load.<>