- Title
- High-pressure crystallography of rhombohedral PrAlO₃ perovskite
- Creator
- Zhao, Jing; Ross, Nancy L.; Angel, Ross J.; Carpenter, Michael A.; Howard, Christopher J.; Pawlak, Dorota A.; Lukasiewicz, Tadeusz
- Relation
- Journal of Physics: Condensed Matter Vol. 21, Issue 23
- Publisher Link
- http://dx.doi.org/10.1088/0953-8984/21/23/235403
- Publisher
- Institute of Physics (IOP) Publishing
- Resource Type
- journal article
- Date
- 2009
- Description
- The evolution of the crystal structure of rhombohedral PrAlO₃ perovskite with pressure has been investigated by single-crystal x-ray diffraction and Raman scattering experiments. The structural evolution as indicated by lattice strains, octahedral tilts, and the distortions of the octahedral AlO₆ and polyhedral PrO₁₂ groups with increasing pressure, is controlled by the relative compressibilities of the AlO₆ octahedra and the PrO₁₂ site. Because the AlO₆ octahedra are more compressible than the PrO₁₂ sites, up to 7.4 GPa the structure evolves towards the high-symmetry cubic phase like any other rhombohedral perovskite. The variation of volume of the rhombohedral phase with pressure can be represented by a third-order Birch–Murnaghan equation of state with bulk modulus K₀ = 193.0(1.2) GPa and K' = 6.6(4). Above 7.4 GPa the evolution towards a cubic phase is interrupted by a phase transition. Observations are consistent with the assignment of Imma symmetry to the high-pressure phase. Comparison with the low-temperature R3̅c to Imma transition confirms that electronic interactions stabilize the Imma phase.
- Subject
- crystal structure; PrAlO₃ perovskite; octahedral AlO₆; polyhedral PrO₁₂
- Identifier
- http://hdl.handle.net/1959.13/916973
- Identifier
- uon:8172
- Identifier
- ISSN:0953-8984
- Language
- eng
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