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Title: Ferroelectric domain structure of anisotropically strained NaNbO{sub 3} epitaxial thin films

NaNbO{sub 3} thin films have been grown under anisotropic biaxial strain on several oxide substrates by liquid-delivery spin metalorganic chemical vapor deposition. Compressive lattice strain of different magnitude, induced by the deposition of NaNbO{sub 3} films with varying film thickness on NdGaO{sub 3} single crystalline substrates, leads to modifications of film orientation and phase symmetry, which are similar to the phase transitions in Pb-containing oxides near the morphotropic phase boundary. Piezoresponse force microscopy measurements exhibit large out-of-plane polarization components, but no distinctive domain structure, while C-V measurements indicate relaxor properties in these films. When tensile strain is provoked by the epitaxial growth on DyScO{sub 3}, TbScO{sub 3}, and GdScO{sub 3} single crystalline substrates, NaNbO{sub 3} films behave rather like a normal ferroelectric. The application of these rare-earth scandate substrates yields well-ordered ferroelectric stripe domains of the type a{sub 1}/a{sub 2} with coherent domain walls aligned along the [001] substrate direction as long as the films are fully strained. With increasing plastic lattice relaxation, initially, a 2D domain pattern with still exclusively in-plane electric polarization, and finally, domains with in-plane and out-of-plane polar components evolve.
Authors:
; ; ;  [1] ;  [2]
  1. Leibniz-Institute for Crystal Growth, Max-Born-Str. 2, 12489 Berlin (Germany)
  2. Forschungszentrum Jülich, Peter Grünberg Institute, Jülich (Germany)
Publication Date:
OSTI Identifier:
22304323
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 115; Journal Issue: 20; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ANISOTROPY; CHEMICAL VAPOR DEPOSITION; DOMAIN STRUCTURE; EPITAXY; FERROELECTRIC MATERIALS; MODIFICATIONS; MONOCRYSTALS; NIOBATES; OXIDES; PHASE TRANSFORMATIONS; POLARIZATION; RARE EARTHS; SODIUM COMPOUNDS; SPIN; STRAINS; SUBSTRATES; SYMMETRY; THICKNESS; THIN FILMS