Superconducting Materials and Devices

This research program was concerned with the study of the phenomena of quantum superconductivity and with the evaluation of the potential for the application of such phenomena in superconducting electronic devices. The initial research efforts were focused on the study of the origin of 1f noise in superconducting tunnel junctions and in ultra-high frequency effects and non- equilibrium phenomena in Josephson junctions. The 1f noise research involved the study of the dynamic behavior of individual electronic defects in very small device structures. It led to the discovery of the reversible fluctuations of atomic defects between metastable configurations as the microscopic source of 1 f noise in tunnel junctions and in compound semiconductor device structures and to the discovery of strong, apparently lattice-mediated interactions, between these defects. With the discovery of high temperature superconductivity HTS partway through this research project a major portion of the research effort was redirected to the effort to fabricate and study high quality cuprate oxide superconductor thin films. This effort resulted in the first demonstration of the in-situ growth of HTS films and in their application in a number of studies that probed the nature of this new phenomenon. JHD