Structural evolution of (Ca0.35Sr0.65)TiO3 perovskite at high pressures

Carpenter, M. A. and Rios, S. and Sondergeld, P. and Crichton, W. A. and Bouvier, P. (2007) Structural evolution of (Ca0.35Sr0.65)TiO3 perovskite at high pressures. Journal of Solid State Chemistry, 180. pp. 360-369.

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Abstract

Lattice parameters of a synthetic powder sample of Ca0.35Sr0.65TiO3 perovskite have been determined by the method of Le Bail refinement, using synchrotron X-ray diffraction patterns collected at pressures up to 15.5 GPa with a membrane-driven diamond anvil cell. At ambient conditions, diffraction data were consistent with the I4/mcm structure reported previously in the literature for the same composition. Diffraction data collected at high pressures were consistent with tetragonal (or, at least, pseudo-tetragonal) lattice geometry, and no evidence was found for the development of any of the orthorhombic structures identified in other studies of (Ca, Sr)TiO3 perovskites. Additional weak reflections, which could not be accounted for by the normal I4/mcm perovskite structure, were detected in diffraction patterns collected at pressures of 0.9–2.5 GPa, and above 13.5 GPa, however. Small anomalies in the evolution of unit cell volume and tetragonal strain were observed near 3 GPa, coinciding approximately with breaks in slope with increasing pressure of bulk and shear moduli for a sample with the same composition which had previously been reported. The anomalies could be due either to new tetragonal2tetragonal/pseudo-tetragonal phase transitions or to subtle changes in compression mechanism of the tetragonal perovskite structure.

Item Type: Article
Uncontrolled Keywords: 2007 AREP IA53 2007 P
Subjects: 03 - Mineral Sciences
Divisions: 03 - Mineral Sciences
Journal or Publication Title: Journal of Solid State Chemistry
Volume: 180
Page Range: pp. 360-369
Depositing User: Sarah Humbert
Date Deposited: 16 Feb 2009 13:01
Last Modified: 23 Jul 2013 10:01
URI: http://eprints.esc.cam.ac.uk/id/eprint/187

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