NUCLEATION AND MOTION OF AN ISOLATED ABRIKOSOV VORTEX

A new family of superconductor-normal-metal-insulator-superconductor (S/I/N/S) Josephson junctions have been developed in which a single Abrikosov vortex can be nucleated and systematically moved to selected positions. The location of the vortex within the junction is determined from the shape of the diffraction patterns. Methods have been developed to push the vortex to most any desired location within the junction by applying currents in either or both of the cross-strip legs of the junction. The elementary pinning force for a vortex in a pure Pb film was measured and found to be much smaller than for a Pb-Bi film. In addition, the vortex moves in much smaller steps for the Pb film than was found for the Pb-Bi films. For S/I/N/S junctions, the voltages and currents are in the microvolt and milliamp range; so very conventional detection can be used if a device is to be built based on the motion of a single Abrikosov vortex.