Influence of trapped flux on critical currents of Josephson junctions

Abstract

This paper investigates the influence of external field on the distribution of the critical current of Josephson junctions. The external field can cause trapped flux which may reduce the critical current. Experimental results show a formation of bunches in the distribution of the critical current when the external magnetic field rises a certain limit. From a theoretical point of view this formation can only be explained by attractive pinning points in the vicinity of the junction. The Josephson junctions were fabricated with the 1 kA/cm2 Nb/Al2O3/Nb trilayer process of FLUXONICS Foundry.