Accession Number : ADA322555

Title :   Synthesis of Ceramics from Solutions: Functionally Graded Composites, NanoComposites and Single Crystal Thin Films. Epitaxial Growth and Structure of Highly Mismatched Oxide Films with Rock-Salt Structure on MgO.

Descriptive Note : Technical rept. no. 2, Dec 95-Nov 96,

Corporate Author : CALIFORNIA UNIV SANTA BARBARA DEPT OF MATERIALS

Personal Author(s) : Langjahr, P. A. ; Wagner, T. ; Lange, F. F. ; Ruehle, M.

PDF Url : ADA322555

Report Date : 28 FEB 1997

Pagination or Media Count : 8

Abstract : CaO thin films were grown on (001) MgO single crystal substrates by a chemical solution deposition method to study the influence of a relatively high lattice mismatch (14%) on the epitaxial growth. In order to minimize an influence of a different crystal structure and chemistry between film and substrate, film and substrate were chosen to have the same structure (NaCl) and a similar chemistry. The films were heat treated until they broke up into single crystal islands on the MgO substrate. X-ray pole figure analysis and TEM observations of the CaO-films showed that most of the grains had a single out-of-plane orientation (111)CaO (parallel lines) (001)MgO, corresponding to two non-redundant, symmetry related in-plane variants 110(111)CaO (parallel lines) 110(001)MgO and 110(111)CaO (parallel lines) 110(001)MgO. A sigma 7/ sigma 8 Near Coincidence Site Lattice (NCSL) model could be constructed for the interface, that suggests good lattice and charge matching for the observed orientation relations. The mechanisms and energetics leading to the experimentally observed orientation relations are discussed.

Descriptors :   *COMPOSITE MATERIALS, *THIN FILMS, *SINGLE CRYSTALS, *EPITAXIAL GROWTH, *CERAMIC MATERIALS, *MAGNESIUM OXIDES, CRYSTAL STRUCTURE, SYNTHESIS, SUBSTRATES, X RAYS, HEAT TREATMENT, CHEMISTRY, DEPOSITION, OXIDES, ENERGETIC PROPERTIES, MATCHING, CALCIUM OXIDES.

Subject Categories : Inorganic Chemistry
      Ceramics, Refractories and Glass
      Laminates and Composite Materials
      Crystallography

Distribution Statement : APPROVED FOR PUBLIC RELEASE