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Title: Elemental intermixing within an ultrathin SrRuO{sub 3} electrode layer in epitaxial heterostructure BaTiO{sub 3}/SrRuO{sub 3}/SrTiO{sub 3}

Aberration corrected scanning transmission electron microscopy is used to directly observe atom columns in an epitaxial BaTiO{sub 3} thin film deposited on a 3.6 nm-thick SrRuO{sub 3} electrode layer above an SrTiO{sub 3} (001) substrate. Compositional gradients across the heterointerfaces were examined using electron energy-loss spectroscopy techniques. It was found that a small amount of Ba and Ti had diffused into the SrRuO{sub 3} layer, and that this layer contained a non-negligible concentration of oxygen vacancies. Such point defects are expected to degrade the electrode’s electronic conductivity drastically, resulting in a much longer screening length. This may explain the discrepancy between experimental measurements and theoretical estimates of the ferroelectric critical thickness of a BaTiO{sub 3} ferroelectric barrier sandwiched between metallic SrRuO{sub 3} electrodes, since theoretical calculations generally assume ideal (stoichiometric) perovskite SrRuO{sub 3}.
Authors:
; ; ;  [1] ;  [1] ;  [2] ;  [3] ; ;  [1] ;  [3] ;  [4] ;  [4] ;  [2]
  1. Key Laboratory of Polar Materials and Devices, Ministry of Education, East China Normal University, Shanghai, 200062 (China)
  2. (Japan)
  3. (China)
  4. Nanostructures Research Laboratory, Japan Fine Ceramics Center, Nagoya 456-8587 (Japan)
Publication Date:
OSTI Identifier:
22492389
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Advances; Journal Volume: 6; Journal Issue: 1; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; BARIUM; CONCENTRATION RATIO; ELECTRIC CONDUCTIVITY; ELECTRONS; ENERGY-LOSS SPECTROSCOPY; EPITAXY; FERROELECTRIC MATERIALS; LAYERS; OXYGEN; RUTHENIUM OXIDES; STOICHIOMETRY; STRONTIUM TITANATES; SUBSTRATES; THIN FILMS; TITANIUM; TRANSMISSION ELECTRON MICROSCOPY; VACANCIES