Please use this identifier to cite or link to this item: http://hdl.handle.net/1959.13/928961

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Title
Pseudoproper ferroelastic softening behaviour and dynamic microstructure of monoclinic PrAlO₃ perovskite
Author/Creator
Carpenter, M. A.;  Wiltshire, E. C.;  Howard, C. J.;  Thomson, R. I.;  Turczynski, S.;  Pawlak, D. A.;  Lukasiewicz, T.
Institution
The University of Newcastle. Faculty of Engineering & Built Environment, School of Engineering
Description
Elastic and anelastic properties of single crystal PrAlO₃ have been investigated by resonant ultrasound spectroscopy at 0.2-1.2 MHz. Non-linear (pseudoproper) softening with falling temperature in the R3̅c stability field below ~690K is related to the elastic stability limit (C₁₁ - C₁₂)C₄₄ → 0. Before this instability point is reached, the first order R3̅c ↔ Imma transition intervenes and is marked by a steep minimum in shear elastic constants. Further pseudoproper ferroelastic softening then occurs, consistent with (C₁₁ - C₁₂) → 0 at ~151K for the second order Imma ↔ C2/m transition. Superattenuation of acoustic resonances within the stability field of the C2/m structure implies that the monoclinic twin walls are highly mobile, apart from in a narrow temperature interval near 100K where the structure becomes metrically tetragonal. PrAlO₃ appears to represent a general class of Jahn–Teller phase transitions in perovskites for which the predominant order parameter transforms according to Γ⁺₃ symmetry and which displays an unusual anelastic dissipation.
Relation
Phase Transitions Vol. 83, Issue 9, p. 703-713
Publisher Link
http://dx.doi.org/10.1080/01411594.2010.491953
Date
2010
Publisher
Taylor and Francis
Keyword(s)
PrAlO₃;  elastic softening;  pseudoproper ferroelastic;  Jahn-Teller;  superattenuation
Resource Type
journal article
Identifier
http://hdl.handle.net/1959.13/928961
Identifier
ISSN:0141-1594
Reviewed
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Subject
"Phase Transitions"
 
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