Josephson Junctions with Nb/Al Composite Electrodes

Abstract

Josephson tunnel junctions have been fabricated incorporporating a thin layer of normal metal which is oxidized to form the tunnel barrier. The tunnel devices tested were of the form Nb/Al/Al2O3/Nb and several milliamperes of Josephson current were observed at 4.2°K. These samples have been found to have better defined tunneling characteristics than samples of the form Nb/NbOx/Nb.