Accession Number : ADA264410


Title :   High Temperature Superconducting Films and Multilayers for Electronics


Descriptive Note : Annual rept. 21 Feb 1992-20 Feb 1993


Corporate Author : WESTINGHOUSE SCIENCE AND TECHNOLOGY CENTER PITTSBURGH PA


Personal Author(s) : Gavaler, John R ; Talvacchio, John


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a264410.pdf


Report Date : 20 Feb 1993


Pagination or Media Count : 31


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.


Descriptors :   *ELECTRONICS , *HIGH TEMPERATURE , *FILMS , *SUPERCONDUCTIVITY , BUFFERS , ANGLES , TEMPERATURE , LAYERS , INSULATION , SUPERCONDUCTORS , STRUCTURES , CORRELATION , SURFACES , CRITICAL TEMPERATURE , TUNNELS , SUBSTRATES , MICROWAVES , EPITAXIAL GROWTH , DIELECTRICS , THIN FILMS , STRONTIUM , BARIUM , RADIOFREQUENCY , SPUTTERING , NEODYMIUM , TUNNELING , CIRCUITS , TITANIUM , GALLIUM , BISMUTH , YTTRIUM , PASSIVITY , POTASSIUM , LANTHANUM , REPRODUCIBILITY , JOSEPHSON JUNCTIONS , BARRIERS , CONSTANTS , ELECTRODES , ALUMINUM , COPPER , OXIDES , OXIDATION , TRANSITION TEMPERATURE , MORPHOLOGY , RESISTANCE , MATERIALS , PARAMETERS , CONDUCTIVITY , METALS , DIGITAL SYSTEMS


Subject Categories : Physical Chemistry
      Electrical and Electronic Equipment
      Coatings, Colorants and Finishes
      Electricity and Magnetism


Distribution Statement : APPROVED FOR PUBLIC RELEASE