Relaxation oscillations in point−contact Josephson junctions

Abstract

Negative resistance regions have been observed on the static I−V curves of point−contact Josephson junctions when dc biased with a low−impedance source. An equivalent circuit model has been developed which successfully explains the experimental results in terms of relaxation oscillations. It is also found that such junctions can be operated either as a one−port amplifier for signals at 5 MHz or as a 36−GHz heterodyne mixer with large conversion gain.