Microstructure dynamics in orthorhombic perovskites

Zhang, Zhiying and Koppensteiner, Johannes and Schranz, Wilfried and Betts, Jonathan B. and Migliori, Albert and Carpenter, Michael A. (2010) Microstructure dynamics in orthorhombic perovskites. Physical Review B, 82 (1). 014113. DOI 10.1103/PhysRevB.82.014113

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Abstract

Anelastic loss mechanisms associated with phase transitions in BaCeO3 have been investigated at relatively high frequency ∼1 MHz and low stress by resonant ultrasound spectroscopy (RUS), and at relatively low frequency ∼1 Hz and high stress by dynamic mechanical analysis (DMA). Changes in the elastic moduli and dissipation behavior clearly indicate phase transitions due to octahedral tilting: Pnma↔Imma↔R3̅ c↔Pm3̅ m structures at 551 K, 670 K, and 1168 K, and strain analysis shows that they are tricritical, first-order, and second-order phase transitions, respectively. Structures with intermediate tilt states (R3̅ c and Imma structures) show substantial anelastic softening and dissipation associated with the mobility of twin walls under applied stress. The Pnma structure shows elastic stiffening which may be due to the simultaneous operation of two discrete order parameters with different symmetries. In contrast with studies of other perovskites, BaCeO3 shows strong dissipation at both DMA and RUS frequencies in the stability field of the Pnma structure. This is evidence that ferroelastic twin walls might become mobile in Pnma perovskites and suggests that shearing of the octahedra may be a significant factor.

Item Type: Article
Uncontrolled Keywords: 2010AREP; IA61;
Subjects: 03 - Mineral Sciences
Divisions: 03 - Mineral Sciences
Journal or Publication Title: Physical Review B
Volume: 82
Page Range: 014113
Identification Number: 10.1103/PhysRevB.82.014113
Depositing User: Sarah Humbert
Date Deposited: 09 Sep 2010 14:41
Last Modified: 23 Jul 2013 10:00
URI: http://eprints.esc.cam.ac.uk/id/eprint/1930

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