Device applications of reactive ion beam sputter deposited superconducting thin films

The technique of Reactive Ion Beam Sputter Deposition has been used in the preparation of metal oxide thin-film composites which have a promising potential for superconducting device applications. We have investigated the correlation between film deposition parameters such as reactive gas (oxygen) partial pressure, substrate temperature, target composition etc., with the film microstructure and superconducting properties. The resulting granular and amorphous films are extremely stable with respect to repeated temperature cycling. We have demonstrated the use of these materials as base electrodes in Josephson tunnel junctions and as weak-link Josephson switches. The extremely smooth surface topography of the films also implies low flux-pinning thresholds which should be useful in fluxoid memory and logic devices.