Superconducting Electronic Film Structures.
Abstract
Data from Nb/Sn and Nb/Al diffusion couple experiments provided supporting evidence for a proposed hypothesis that superconducting A15 compounds are formed via an oxygen catalyzed reaction. Both epitaxy, and the addition of an impurity (carbon) were successful in increasing the critical temperatures of NbN deposited at low temperature. Critical temperatures of over 16K were obtained in epitaxially grown NbN films sputtered on substrates held at less than 100 C. RHEED and X-ray rocking curve data show that the new UHV deposition and analytical facility has the capability for epitaxially growing high quality single crystals of the technologically important A15 and B1 superconductors. Low-leakage all-NbN tunnel junctions have been developed with ion-beam oxidized A1 and Mg barriers, or rf-sputtered MgO barriers. The first Nb-Sn based junctions with refractory counterelectrodes were fabricated. XPS, RHEED, and tunneling have been used to characterize: 1) the structure of epitaxial films, 2) the role of ion-beam oxidation in the preparation of tunnel barriers that can be used with refractory counterelectrodes, and 3) anisotropic surface oxide growth on single-crystal films. Nb single crystal films were prepared which have three times lower rf surface losses compared to polycrystalline Nb. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 05, 1985
- Accession Number
- ADA166183
Entities
People
- A. I. Braginski
- J. R. Gavaler