The influence of vanadium oxide on the properties of Josephson tunnel junctions

The properties of VNb-NbOsub(x)-Pb and NbV-VOsub(x)-Pb Josephson tunnel junctions are investigated. The behaviour of the VNb-NbOsub(x)-Pb junctions is as expected for tunnels with proximity effect. The junctions with the VOsub(x) barriers have anomalous small critical currents and very large excess currents. Both, the temperature dependence of the critical current and the excess current of these junctions deviate strongly from that of other known tunnel junctions. The interaction of the tunneling electrons with strong internal magnetic fields within the VOsub(x) is discussed as a possible reason of these deviations. (author)