- Title
- Pseudoproper ferroelastic softening behaviour and dynamic microstructure of monoclinic PrAlO₃ perovskite
- Creator
- Carpenter, M. A.; Wiltshire, E. C.; Howard, C. J.; Thomson, R. I.; Turczynski, S.; Pawlak, D. A.; Lukasiewicz, T.
- Relation
- Phase Transitions Vol. 83, Issue 9, p. 703-713
- Publisher Link
- http://dx.doi.org/10.1080/01411594.2010.491953
- Publisher
- Taylor and Francis
- Resource Type
- journal article
- Date
- 2010
- 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.
- Subject
- PrAlO₃; elastic softening; pseudoproper ferroelastic; Jahn-Teller; superattenuation
- Identifier
- http://hdl.handle.net/1959.13/928961
- Identifier
- uon:10496
- Identifier
- ISSN:0141-1594
- Language
- eng
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