Critical currents of Nb-NbOx-Pb tunnel junctions with high normal resistance

Abstract

Generally the relation between the normal tunneling resistance and the critical Josephson current is given by the equation of Ambegaokar' and Baratoff /l/. In the case of tunnel junctions with high resistance one has to expect deviations f r o m these equations because here fluctuations begin to be important and the critical currents will be smaller. We report our experimental results concerning these deviations