Barrier composition and electrical properties of high-quality all-niobium Josephson tunnel junctions

Abstract
A fabrication procedure for all‐niobium tunnel junctions with oxide tunnel barriers is described. All steps of the tunnel‐barrier growth have been characterized in situ with the help of x‐ray photoelectron spectroscopy. The chemical composition of the barrier is described, and the properties of devices discussed. The results demonstrate the application potential of these all‐refractory junctions.