The role of orbital ordering in the tetragonal-to-cubic phase transition in CuCr{sub 2}O{sub 4}
- School of Chemistry, University of Sydney, Sydney NSW 2006 (Australia)
Copper(II) chromite (CuCr{sub 2}O{sub 4}) undergoes a first-order structural transition from a tetragonal distorted spinel structure in space group (I4{sub 1}/amd) to a cubic spinel structure in Fd3-bar m, near 600 deg. C. The transition has been followed using synchrotron X-ray powder diffraction between room temperature and 750 deg. C. The structure changes as a consequence of a transition from an orbitally ordered to orbital disordered state associated with a Jahn-Teller-type distortion of the CuO{sub 4} tetrahedron. The orbital melting results in a small increase in cell volume. - Graphical abstract: The first-order tetragonal-cubic phase transition in CuCr{sub 2}O{sub 4} is accompanied by a noticeably reduction in cell volume associated with the loss of orbital ordering present in the low-temperature Jahn-Teller distorted tetragonal structure.
- OSTI ID:
- 21128435
- Journal Information:
- Journal of Solid State Chemistry, Vol. 181, Issue 9; Other Information: DOI: 10.1016/j.jssc.2008.05.018; PII: S0022-4596(08)00248-X; Copyright (c) 2008 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
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