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Title: Stoichiometry of LaAlO{sub 3} films grown on SrTiO{sub 3} by pulsed laser deposition

We have studied the stoichiometry of epitaxial LaAlO{sub 3} thin films on SrTiO{sub 3} substrate grown by pulsed laser deposition as a function of laser energy density and oxygen pressure during the film growth. Both x-ray diffraction ({theta}-2{theta} scan and reciprocal space mapping) and transmission electron microscopy (geometric phase analysis) revealed a change of lattice constant in the film with the distance from the substrate. Combined with composition analysis using x-ray fluorescence we found that the nominal unit-cell volume expanded when the LaAlO{sub 3} film was La-rich, but remained near the bulk value when the film was La-poor or stoichiometric. La excess was found in all the films deposited in oxygen pressures lower than 10{sup -2} Torr. We conclude that the discussion of LaAlO{sub 3}/SrTiO{sub 3} interfacial properties should include the effects of cation off-stoichiometry in the LaAlO{sub 3} films when the deposition is conducted under low oxygen pressures.
Authors:
; ;  [1] ; ; ; ; ;  [2]
  1. Department of Physics, Temple University, Philadelphia, Pennsylvania 19122 (United States)
  2. Department of Materials Science and Engineering, Drexel University, Philadelphia, Pennsylvania 19104 (United States)
Publication Date:
OSTI Identifier:
22122809
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 114; Journal Issue: 2; Other Information: (c) 2013 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ALUMINATES; ENERGY BEAM DEPOSITION; ENERGY DENSITY; EPITAXY; FLUORESCENCE; INTERFACES; LANTHANUM COMPOUNDS; LASER RADIATION; LATTICE PARAMETERS; LAYERS; PHASE STUDIES; PULSED IRRADIATION; STOICHIOMETRY; STRONTIUM TITANATES; SUBSTRATES; THIN FILMS; TRANSMISSION ELECTRON MICROSCOPY; X RADIATION; X-RAY DIFFRACTION; X-RAY FLUORESCENCE ANALYSIS