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Structural characterization of yttria (Y2O3) inclusions in YBa2Cu3O7−x films : Growth model and effect on critical current density

Selinder, T.I. ; Helmersson, U. ; Han, Z. and Wallenberg, LR LU (1993) In Thin Solid Films 229(2). p.237-248
Abstract
A higher critical current and enhanced pinning was obtained in c-axis-oriented YBa2Cu3O7−x (YBCO)films having a higher density of semicoherent yttria (Y2O3) inclusions. The films were grown by sputtering and the inclusion density depends on the fraction of N2O in the sputtering gas. The inclusions were studied by transmission electron microscopy, both in planar sections and in cross-sections. They are embedded in the YBCO matrix without disturbing its structure appreciably, and the inclusion density is up to about 1017 cm−3, comprising about 4% of the film volume. From the appearance of moiré fringes and from high resolution transmission electron micrographs, it is concluded that the inclusions are highly oriented and have coherent or... (More)
A higher critical current and enhanced pinning was obtained in c-axis-oriented YBa2Cu3O7−x (YBCO)films having a higher density of semicoherent yttria (Y2O3) inclusions. The films were grown by sputtering and the inclusion density depends on the fraction of N2O in the sputtering gas. The inclusions were studied by transmission electron microscopy, both in planar sections and in cross-sections. They are embedded in the YBCO matrix without disturbing its structure appreciably, and the inclusion density is up to about 1017 cm−3, comprising about 4% of the film volume. From the appearance of moiré fringes and from high resolution transmission electron micrographs, it is concluded that the inclusions are highly oriented and have coherent or semicoherent interfaces towards matrix. A model for formation of the yttria inclusions during film growth is presented, which includes nucleation of epitaxial coherent yttria islands, layer-by-layer growth and finally overgrowth by advancing steps of the YBCO film. The enhanced pinning and transport critical current densities, relation to film microstructure and the possible flux-pinning mechanisms by these yttria inclusions are discussed. (Less)
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organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Thin Solid Films
volume
229
issue
2
pages
12 pages
publisher
Elsevier
external identifiers
  • scopus:0027607065
ISSN
0040-6090
DOI
10.1016/0040-6090(93)90371-U
language
English
LU publication?
yes
id
3035c105-e4a0-4238-b6b3-c75fd2492bb8
date added to LUP
2023-10-31 15:29:26
date last changed
2023-11-02 10:20:36
@article{3035c105-e4a0-4238-b6b3-c75fd2492bb8,
  abstract     = {{A higher critical current and enhanced pinning was obtained in c-axis-oriented YBa2Cu3O7−x (YBCO)films having a higher density of semicoherent yttria (Y2O3) inclusions. The films were grown by sputtering and the inclusion density depends on the fraction of N2O in the sputtering gas. The inclusions were studied by transmission electron microscopy, both in planar sections and in cross-sections. They are embedded in the YBCO matrix without disturbing its structure appreciably, and the inclusion density is up to about 1017 cm−3, comprising about 4% of the film volume. From the appearance of moiré fringes and from high resolution transmission electron micrographs, it is concluded that the inclusions are highly oriented and have coherent or semicoherent interfaces towards matrix. A model for formation of the yttria inclusions during film growth is presented, which includes nucleation of epitaxial coherent yttria islands, layer-by-layer growth and finally overgrowth by advancing steps of the YBCO film. The enhanced pinning and transport critical current densities, relation to film microstructure and the possible flux-pinning mechanisms by these yttria inclusions are discussed.}},
  author       = {{Selinder, T.I. and Helmersson, U. and Han, Z. and Wallenberg, LR}},
  issn         = {{0040-6090}},
  language     = {{eng}},
  month        = {{06}},
  number       = {{2}},
  pages        = {{237--248}},
  publisher    = {{Elsevier}},
  series       = {{Thin Solid Films}},
  title        = {{Structural characterization of yttria (Y2O3) inclusions in YBa2Cu3O7−x films : Growth model and effect on critical current density}},
  url          = {{http://dx.doi.org/10.1016/0040-6090(93)90371-U}},
  doi          = {{10.1016/0040-6090(93)90371-U}},
  volume       = {{229}},
  year         = {{1993}},
}