High transition temperature superconducting thin films: in-situ growth, processing and properties

A high-pressure reactive evaporation process and a high-pressure reactive sputtering process have been developed for the growth of high-quality thin films of YBa/sub 2/CU/sub 3/O/sub 7/. Both techniques, when used with heated substrates, are effective in the formation of the 123 phase in situ during the film growth. With reactive evaporation only a cooldown anneal in a higher pressure oxygen ambient is necessary to obtain good superconducting properties. For the reactive sputtering process, a brief, postgrowth, rapid thermal anneal is required for best results. Fully epitaxial growth has been achieved with single-crystal MgO substrates. The resultant films, which can be quite smooth and uniform, have been patterned to micron and submicron dimensions, and the transport properties of these microstructures have been examined. Results are presented on critical currents and Josephson weak links.<>