Structural relationships and a phase diagram for (Ca,Sr)TiO3 perovskites

Carpenter, M. A. and Howard, C. J. and Knight, K. S. and Zhang, Z. (2006) Structural relationships and a phase diagram for (Ca,Sr)TiO3 perovskites. Journal of Physics: Condensed Matter, 18 (48). pp. 10725-10750. DOI 10.1088/0953-8984/18/48/002

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Abstract

Sets of lattice parameter data have been obtained from high resolution neutron and synchrotron x-ray powder diffraction patterns collected in situ as a function of temperature for perovskites in the (Ca,Sr)TiO3 solid solution. An updated phase diagram is proposed in which there is a stability field for the I4/mcm structure at all compositions across the solid solution. The transition is close to tricritical in the composition range 0–70% SrTiO3 component and then evolves towards second order character (Landau 246 solution) in the range 85–100% SrTiO3. Transition temperatures as a function of composition for and transitions at lower temperatures show a break in slope at ~60% SrTiO3. Variations of octahedral tilt angles and spontaneous strains are much the same for Pbcm structures as they are for Pnma structures. Nearly cubic lattice geometry of orthorhombic structures at intermediate compositions is ascribed to only weak coupling between octahedral tilting and the shear strain e4. The phase diagram topology and variations in structural evolution at different compositions indicate that there is a distinct change in the behaviour of the solid solution at ~85% SrTiO3.

Item Type: Article
Uncontrolled Keywords: 2006 AREP IA52 2006 P
Subjects: 03 - Mineral Sciences
Divisions: 03 - Mineral Sciences
Journal or Publication Title: Journal of Physics: Condensed Matter
Volume: 18
Page Range: pp. 10725-10750
Identification Number: 10.1088/0953-8984/18/48/002
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/185

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