The critical current of miniature thin film Josephson junctions with high current densities

Nb-NbOsub(x)-Pb tunnel junctions with areas of about 10 x 10 μm2 and high current densities are prepared by cleaning the niobium surface in a rf glow discharge. The dependence of the critical Josephson currents on magnetic field is investigated. To a first approximation the behaviour of the critical current is described by the theory of one-dimensional junctions. Critical current densities up to 2 x 105 A/cm2 are reached. (author)