Growth mechanisms of layered superconductors
Using a combination of Z-contrast imaging, scanning tunneling microscopy, and plan view diffraction contrast imaging, we have studied the growth and relaxation mechanisms of YBa{sub 2}Cu{sub 3}O{sub 7-x} deposited on MgO and SrTiO{sub 3} substrates. Two-dimensional island growth occurs on SrTiO{sub 3} substrates, with relaxation through the nucleation of dislocation half-loops. Then the threading dislocation segments with a screw component can lead to kinetic roughening through the development of growth pyramids. In contrast, growth on MgO occurs by true one-dimensional island growth (with no wetting layer), most of the interface being incommensurate with the substrate (although crystallographically aligned). Dislocations with both edge and screw components are generated on island coalescence. A highly anisotropic surface energy is shown to responsible for cell-by-cell c{perpendicular} growth being thermodynamically preferred, although at high supersaturations a transition a{perpendicular} growth occurs.
- Research Organization:
- Oak Ridge National Lab., TN (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC05-84OR21400
- OSTI ID:
- 10167061
- Report Number(s):
- CONF-920402-48; ON: DE92018492
- Resource Relation:
- Conference: 1992 Material Research Society (MRS) spring meeting,San Francisco, CA (United States),27 Apr - 2 May 1992; Other Information: PBD: Jun 1992
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
HIGH-TC SUPERCONDUCTORS
CRYSTAL GROWTH METHODS
LAYERS
YTTRIUM OXIDES
BARIUM OXIDES
COPPER OXIDES
SUBSTRATES
MAGNESIUM OXIDES
TITANIUM OXIDES
SCANNING ELECTRON MICROSCOPY
SUPERLATTICES
NUCLEATION
CRYSTAL GROWTH
DISLOCATIONS
SURFACE ENERGY
ANISOTROPY
360201
PREPARATION AND FABRICATION