Hysteretic behavior of signal amplification using SNS junctions

A superconductor-normal metal-superconductor junction (SNS junction) has a nonlinear current-voltage characteristic (CVC) that may exhibit the low-vol tage negative differential resistance (LVNDR) effect. Taking advantage of t his remarkable effect it may be possible to associate a SNS junction to con ventional electronic circuits in order to design devices such as oscillator s, amplifiers and mixers. This work simulates the output signal of an ampli fier device, which is essentially a SNS junction connected with an adjustab le DC voltage supplier, and an AC signal source, which could be a SNS junct ion as well. Sometimes the LVNDR effect is hidden under a low-voltage hyste resis on the CVC because the experiment has been performed in a current-bia s measuring setup. We focus on the question of this hysteretic behavior and discuss the performance of the proposed device with and without hysteresis . (C) 2001 Elsevier Science B.V. All rights reserved.