Microstructure dynamics in orthorhombic perovskites

Autor(en)

Zhiying Zhang, Johannes Koppensteiner, Wilfried Schranz, Jonathan B. Betts, Albert Migliori, Michael Allan Carpenter

Abstrakt

Anelastic loss mechanisms associated with phase transitions in BaCeO3 have been investigated at relatively high frequency similar to 1 MHz and low stress by resonant ultrasound spectroscopy (RUS), and at relatively low frequency similar to 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. R (3) over barc. R (3) over barc 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 (R (3) over barc 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.

Organisation(en)

Physik Funktioneller Materialien

Externe Organisation(en)

University of Cambridge, National High Magnetic Field Laboratory

Journal

Physical Review B

Band

82

Anzahl der Seiten

10

ISSN

1098-0121

DOI

https://doi.org/10.1103/PhysRevB.82.014113

Publikationsdatum

2010

Peer-reviewed

Ja

ÖFOS 2012

1030 Physik, Astronomie

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/73393f6f-253e-46df-8da9-34def2ea3792