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Title: Nature of size-dependent lattice distortions in doped CeO{sub 2}

Electron paramagnetic resonance spectroscopy of Gd{sup 3+} probe ions is used to investigate the nature of size dependent lattice distortions in bulk and nanocrystalline CeO{sub 2} with crystallite sizes of 600 and 10 nm, respectively, and doped with 0.5 and 1 cation% Y. The Gd{sup 3+} ions in bulk CeO{sub 2} are primarily located in almost perfect cubic crystal field, and the presence of the nearest neighbor vacancies results in trigonal distortion of this crystal field. In contrast, for nanocrystalline ceria, although the long-range symmetry remains unchanged, decreasing size results in local distortion of the crystal-field that is significantly different than that induced by the presence of nearest-neighbor oxygen vacancies. Different types of distortions are observed for the cation sites in the core and the surface regions of the nanocrystallites. Such lattice distortions at short-range are fundamental to the nanocrystalline state, being related to the increased ratio of the surface:bulk energy at nanometer length scales and provides mechanistic understanding of previously reported lattice parameter changes and phase transitions in nanocrystalline oxides.
Authors:
; ;  [1] ; ;  [2] ;  [3]
  1. MRS Laboratory, Kazan Federal University, Kremlevskaya 18, 420008 Kazan (Russian Federation)
  2. Faculty of Physics and Earth Sciences, University of Leipzig, Linnéstr. 5, D-04103 Leipzig (Germany)
  3. Department of Chemical Engineering and Materials Science, University of California at Davis, Davis, California 95616 (United States)
Publication Date:
OSTI Identifier:
22258727
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 114; Journal Issue: 20; Other Information: (c) 2013 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; CATIONS; CERIUM OXIDES; CRYSTAL FIELD; CRYSTALS; DOPED MATERIALS; ELECTRON SPIN RESONANCE; GADOLINIUM IONS; LATTICE PARAMETERS; NANOSTRUCTURES; PHASE TRANSFORMATIONS; SPECTROSCOPY; SYMMETRY; VACANCIES