A new Josephson junction with a very short barrier length and a very low capacitance

Abstract

Josephson junctions of a new geometrical structure were fabricated and have turned out to be of good quality. They are almost-planar niobium-based bismuth-barrier Josephson junctions which have a barrier length of 75 nm and a capacitance of 0.04 pF. The amplitudes of the zero-voltage current and microwave-induced constant-voltage current steps periodically vanish several times as the power of the applied microwave radiation increases monotonically. The junctions suffer from no degradation due to interdiffusion of metals at room temperature. They are very resistant to unavoidable electrical pulses.