Flux flow microelectronics

Flux-flow-based devices such as the superconducting flux flow transistor and magnetically controlled long junctions have been made from thin films of TlCaBaCuO and YBaCuO. The devices are based on the magnetic control of flux flow in their respective structures: a long junction or an array of weak links. The equivalent circuits of the two devices are similar: a low-impedance input control line, an output impedance of 3-20 Omega , and an active current-controlled element. The long junctions have tended to be slower, to have lower gain, and to be somewhat less noisy than their counterparts. Circuits such as narrowband and distributed amplifiers (50-GHz bandwidths, noise figures <3 dB), phase shifters (continuous with <2-dB loss, 4-40 GHz), logic gates (2-3-ps gate delays). and memories made using these devices are compared and analyzed in terms of performance.<>