Investigations of the current density distribution in NbNbOxPb tunnel junctions

Abstract

Current density distributions in some NbNbOxPb tunnel junctions with dimensions of 100 × 100 μm2 to 10 × 10 μm2 are calculated. The calculations are made on base of new theoretical equations for the dependence of critical current on the magnetical field. The differences in the current density distributions between tunnel junctions with dimensions of 10 × 10 μm2 and dimensions of 30 × 30 μm2 and 100 × 100 μm2 are interpreted by the activity of special processes at the formation of the tunnel barrier. Moreover the investigations show, that an increase of the oxygen fraction at the formation of the tunnel barrier cause an increase of the tunnel junction resistor. But the current density distribution will be not modified qualitatively by this.