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Title: Crystal structures and phase transitions in Sr doped Ba{sub 2}InTaO{sub 6} perovskites

The crystal structures of the double perovskites of the type Ba{sub 2−x}Sr{sub x}InTaO{sub 6} have been studied by synchrotron X-ray and neutron powder diffraction methods. The structures are based on ordered array of the tilted InO{sub 6} and TaO{sub 6} octahedra, with the Ba/Sr cations being completely disordered. The structure evolves from cubic to monoclinic Fm3{sup ¯}m→{sup x∼0.6}I4/m→{sup x∼1.2}I2/m→{sup x∼1.6}P2{sub 1}/n. The changes in the symmetry induced by replacing the Ba with Sr have been identified by a symmetry-mode analysis. Variable temperature S-XRD studies of selected examples have shown that heating the samples induces the same sequence of transitions observed in the composition dependent studies. - Graphical abstract: The evolution of the structure of the B-site ordered perovskites has been determined by high resolution powder diffraction. The nature of the transitions are probed by examination of the symmetry-adapted modes. Display Omitted - Highlights: • Synthesis of Ba{sub 2−x}Sr{sub x}InTaO{sub 6} cation ordered perovskites. • Synchrotron X-ray and neutron diffraction structural studies of Ba{sub 2−x}Sr{sub x}InTaO{sub 6}. • Phase transitions in Ba{sub 2−x}Sr{sub x}InTaO{sub 6}. • Symmetry-adapted mode analysis of phase transitions.
Authors:
;  [1] ;  [1] ;  [2]
  1. School of Chemistry, The University of Sydney, Sydney, NSW 2006 Australia (Australia)
  2. Bragg Institute, Australian Nuclear Science and Technology Organisation, Private Mail Bag 1, Menai, NSW 2234 (Australia)
Publication Date:
OSTI Identifier:
22274114
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Solid State Chemistry; Journal Volume: 206; Other Information: Copyright (c) 2013 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; CATIONS; CUBIC LATTICES; DOPED MATERIALS; INDIUM OXIDES; MONOCLINIC LATTICES; NEUTRON DIFFRACTION; PEROVSKITES; PHASE TRANSFORMATIONS; SYNCHROTRONS; X RADIATION; X-RAY DIFFRACTION