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Title: Symmetry determination on Pb-free piezoceramic 0.5Ba(Zr{sub 0.2}Ti{sub 0.8})O{sub 3}-0.5(Ba{sub 0.7}Ca{sub 0.3})TiO{sub 3} using convergent beam electron diffraction method

(1−x)(Ba(Zr{sub 0.2}Ti{sub 0.8})O{sub 3}-x(Ba{sub 0.7}Ca{sub 0.3})TiO{sub 3} (BZT-xBCT) Pb-free piezoceramic has been reported showing ultrahigh piezoelectric performance in its morphotropic phase boundary (MPB) region. However, the crystal structure characteristic for the MPB composition of BZT-xBCT is still under debate—between single orthorhombic phase and tetragonal + rhombohedral two phase mixture. In the present study, we perform the local symmetry determination on the MPB composition x = 0.5 using convergent beam electron diffraction analysis (CBED). Our CBED results from multiple zone axes suggest that there are two coexisting phases with the point group symmetries of 4 mm (tetragonal) and 3 m (rhombohedral) respectively, which agree with two phase mixture model. The strong piezoelectricity can thus be understood by considering the polarization rotation between tetragonal and rhombohedral phases by external field.
Authors:
;  [1] ; ;  [1] ;  [2] ;  [3] ;  [4] ;  [1] ;  [2] ;  [5]
  1. Multi-Disciplinary Materials Research Center, State Key Lab of Electrical Insulation and Power Equipment and Frontier Institute of Science and Technology, Xi'an, 710049 (China)
  2. (China)
  3. Ferroic Physics Group, National Institute for Materials Science, Tsukuba, 305-0047, Ibaraki (Japan)
  4. Electron Microscopy Group, National Institute for Materials Science, Tsukuba, 305-0047, Ibaraki (Japan)
  5. (Japan)
Publication Date:
OSTI Identifier:
22278108
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 115; Journal Issue: 5; 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; BARIUM COMPOUNDS; CALCIUM COMPOUNDS; ELECTRON BEAMS; ELECTRON DIFFRACTION; MIXTURES; ORTHORHOMBIC LATTICES; PIEZOELECTRICITY; POLARIZATION; SYMMETRY; TITANATES; TRIGONAL LATTICES; ZIRCONIUM COMPOUNDS