A Study of Low-Temperature Processes in Non-Equilibrium Electronic States

摘要

Primary focus was directed to experimental studies of the electrical behavior of weakly-coupled superconductors. Two types of superconducting devices were used, Josephson tunnel junctions and superconducting thin-film microbridges. The experiments showed that non-equilibrium states created by microwave irradiation and quasiparticle injection will change the current - voltage characteristics of Josephson devices. Experiments were also conducted to determine if the grain size of superconducting niobium (Nb) films could be controlled using scanning laser annealing. Initial (as deposited) grain sizes were dependent upon the deposition technique. Regardless, laser annealing resulted in substantial modifications to the structure of the Nb films. With proper laser annealing techniques, relatively fine-grained polycrystalline films were converted to large polycrystalline grains with an average size of 5 by 10 micrometers. (Author)