Microstructure of YBa/sub 2/Cu/sub 3/O/sub 7-//sub x/ thin films grown on single-crystal SrTiO/sub 3/

Journal Article · Thu Jun 15 04:00:00 EDT 1989 · J. Appl. Phys.; (United States)

DOI:https://doi.org/10.1063/1.343222· OSTI ID:6293588

Chan, S; Hwang, D M; Nazar, L

YBa/sub 2/Cu/sub 3/O/sub 7-//sub x/ thin films on (001) and (014) SrTiO/sub 3/ were prepared by coevaporation of Y, BaF/sub 2/, and Cu, and annealing in oxygen at 850 /sup 0/C. Cross-sectional samples prepared by cutting films and substrates along the SrTiO/sub 3/ (100) plane were studied with transmission electron microscopy. The growth of YBa/sub 2/Cu/sub 3/O/sub 7-//sub x/ in as-deposited films is extremely anisotropic with the (001) being the slow direction and the (001) plane being the fast growth plane. When the (001) planes of YBa/sub 2/Cu/sub 3/O/sub 7-//sub x/ grains are parallel to the film plane, as on (001) SrTiO/sub 3/, there is a dominance of this orientation over the whole film. Three types of YBa/sub 2/Cu/sub 3/O/sub 7-//sub x/ grains, 90/sup 0/ misoriented from each other, are observed to grow on both (001) and (014) surfaces of single-crystal SrTiO/sub 3/ substrates with their c directions aligned with one of the three <100> directions of cubic SrTiO/sub 3/. This ambiguity creates a threefold degenerate epitaxy of YBa/sub 2/Cu/sub 3/O/sub 7-//sub x/ on SrTiO/sub 3/, which results in 90/sup 0/ grain boundaries in the final YBa/sub 2/Cu/sub 3/O/sub 7-//sub x/ thin films. These boundaries are free of any second phase and decorations. While some extraneous phases were observed in these films, they were located away from the crystallographically special, 90/sup 0/ boundaries. Therefore, the presence of extraneous phases elsewhere in the films was not damaging to the superconducting transport.

• Research Organization: Bellcore, Red Bank, New Jersey 07701
• OSTI ID: 6293588
• Journal Information: J. Appl. Phys.; (United States), Journal Name: J. Appl. Phys.; (United States) Vol. 65:12; ISSN JAPIA
• Country of Publication: United States
• Language: English

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