23 August 1988 In-Situ Fabrication, Processing And Characterization Of Superconducting Oxide Films
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Proceedings Volume 0948, High-Tc Superconductivity: Thin Films and Devices; (1988) https://doi.org/10.1117/12.947476
Event: Advances in Semiconductors and Superconductors: Physics and Device Applications, 1988, Newport Beach, CA, United States
Abstract
Surfaces of Y1Ba2Cu3O7 (YBCO) are known to react with H2O and CO2 in the ambient atmosphere. The in-situ approach to thin film fabrication and characterization in a closed system makes it possible to investigate the near-surface properties of superconducting YBCO films in the absence of such deleterious reactions. We have fabricated and analyzed superconducting, epitaxial YBCO films entirely or partly in-situ. Oxygen partial pressures during deposition ranged from < 10-9 torr to > 3 X 10-4 torr and temperatures from 400 to > 650°C, producing either amorphous or crystalline deposits. We found that annealing of oxygen-deficient amorphous deposits in oxygen caused atomic segregation of Ba and Y to the surface with a corresponding depletion in Cu. This effect made near-surface layers nonsuperconducting even in the absence of H2O or CO2. Fast heating to crystallization temperature minimized the segregation. Measurements of dc contact resistance, R , and I-V characteristics in cross-strip junctions of YBCO/Au/Nb and YBCO/Au/MgO/Nb indicated near-zero Rc and weak-link I-V characteristics which proved that the in-situ approach permits one to obtain superconducting YBCO film surfaces. In the case of crystalline film deposition at 650°C, the in-situ electron-diffraction of SrTiO3 substrates and 40 to 100 Å thick YBCO films revealed epitaxial crystallization only on clean substrates.
© (1988) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
A. I. Braginski, A. I. Braginski, J. Talvacchio, J. Talvacchio, J. R. Gavaler, J. R. Gavaler, M. G. Forrester, M. G. Forrester, M. A. Janocko, M. A. Janocko, } "In-Situ Fabrication, Processing And Characterization Of Superconducting Oxide Films", Proc. SPIE 0948, High-Tc Superconductivity: Thin Films and Devices, (23 August 1988); doi: 10.1117/12.947476; https://doi.org/10.1117/12.947476
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