Composition and temperature dependent phase transitions in Co-W double perovskites, a synchrotron X-ray and neutron powder diffraction study

Journal Article · Thu Feb 15 00:00:00 EST 2007 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2006.10.038· OSTI ID:21015681

Qingdi, Zhou ^[1]; Elcombe, Margaret M ^[2]

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1. Faculty of Science, School of Chemistry, Centre for Structural Biology and Structural Chemistry, University of Sydney, Chemistry Building (F11), Sydney, New South Wales 2006 (Australia)
2. Bragg Institute, ANSTO, Menai, New South Wales 2234 (Australia)

High-resolution synchrotron and neutron powder diffraction techniques were used to determine precise structures for the series of perovskite oxides A{sub 2-x}Sr{sub x}CoWO{sub 6} (A=Ca, or Ba, 0=<x=<2). The studies demonstrated that the symmetry decreases as the average size of the A-site cation decreases with a sequential introduction of in-phase and out-of-phase tilting of the BO{sub 6} octahedra. A cubic structure in Fm3-bar m with rock-salt like ordering of the Co and W cations was formed for Ba{sub 2-x}Sr{sub x}CoWO{sub 6} with x{approx}<1.4. As the Sr content was increased, the materials became tetragonal in I4/m and ultimately monoclinic in P2{sub 1}/n. A mixture of monoclinic and tetragonal phases occurs in Sr{sub 2}CoWO{sub 6} at room temperature but this was purely monoclinic at 20K.

• OSTI ID: 21015681
• Journal Information: Journal of Solid State Chemistry, Vol. 180, Issue 2; Other Information: DOI: 10.1016/j.jssc.2006.10.038; PII: S0022-4596(06)00568-8; Copyright (c) 2006 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0022-4596
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
BARIUM COMPOUNDS
CALCIUM COMPOUNDS
CATIONS
COBALT COMPOUNDS
CUBIC LATTICES
MIXTURES
MONOCLINIC LATTICES
NEUTRON DIFFRACTION
OXIDES
PEROVSKITE
PHASE TRANSFORMATIONS
STRONTIUM COMPOUNDS
SYMMETRY
TEMPERATURE DEPENDENCE
TEMPERATURE RANGE 0273-0400 K
TETRAGONAL LATTICES
TUNGSTEN COMPOUNDS
X RADIATION