High Temperature Superconducting Films and Multilayers for Electronics
Abstract
Progress is reported on four tasks which address problems fundamental to the understanding of the superconducting state in HTS films, the application of HTS films in passive microwave circuits, the realization of HTS digital electronics, and the development of new superconducting devices. An anti- correlation between critical temperature an normal state resistivity was observed at certain compositions in the YBCO, LSCO, and BKBO systems. The criticality of optimizing both oxidation steps involved in YBCO growth to obtain low rf surface resistances was demonstrated. A new insulating material, Sr-Al- Ta-0 (SAT), was developed as an epitaxial insulator in multilayer YBCO circuits to replace Sr-Ti-O. The dc resistivity and surface morphology were as good as those of Sr-Ti-O while the real and imaginary parts of the dielectric constant were greatly superior. Systematic studies were made of the processing parameters for step-edge S-N-S YBCO Josephson junctions. The critical parameters for junction reproducibility were found to be a step angle of approximately 15 deg and a high-conductivity normal-metal barrier. All-BKBO tunnel junctions were demonstrated with Sr-Ti-O tunnel barriers which exhibited a superconducting gap structure to within 2K of the transition temperature of the BKBO electrodes. Epitaxial Sr-Ti-O films were also used as buffer layers to permit single- orientation BKBO films to be grown on practical La-Al-0 or Nd-Ga-0 substrates. Superconductors, Yttrium, Barium, Cooper, Oxides, High, Critical, Temperature, Thin films, Tunneling, Barriers, Sputtering.
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 20, 1993
- Accession Number
- ADA264410
Entities
People
- John R. Gavaler
- John Talvacchio