Document Detail

High-pressure crystal structure of elastically isotropic CaTiO(3) perovskite under hydrostatic and non-hydrostatic conditions.
MedLine Citation:
PMID:  22037221     Owner:  NLM     Status:  Publisher    
The structural evolution of orthorhombic CaTiO(3) perovskite has been studied using high-pressure single-crystal x-ray diffraction under hydrostatic conditions up to 8.1 GPa and under a non-hydrostatic stress field formed in a diamond anvil cell (DAC) up to 4.7 GPa. Under hydrostatic conditions, the TiO(6) octahedra become more tilted and distorted with increasing pressure, similar to other 2:4 perovskites. Under non-hydrostatic conditions, the experiments do not show any apparent difference in the internal structural variation from hydrostatic conditions and no additional tilts and distortions in the TiO(6) octahedra are observed, even though the lattice itself becomes distorted due to the non-hydrostatic stress. The similarity between the hydrostatic and non-hydrostatic cases can be ascribed to the fact that CaTiO(3) perovskite is nearly elastically isotropic and, as a consequence, its deviatoric unit-cell volume strain produced by the non-hydrostatic stress is very small; in other words, the additional octahedral tilts relevant to the extra unit-cell volume associated with the deviatoric unit-cell volume strain may be totally neglected. This study further addresses the role that three factors-the elastic properties, the crystal orientation and the pressure medium-have on the structural evolution of an orthorhombic perovskite loaded in a DAC under non-hydrostatic conditions. The influence of these factors can be clearly visualized by plotting the three-dimensional distribution of the deviatoric unit-cell volume strain in relation to the cylindrical axis of the DAC and indicates that, if the elasticity of a perovskite is nearly isotropic as it is for CaTiO(3), the other two factors become relatively insignificant.
Jing Zhao; Nancy L Ross; Di Wang; Ross J Angel
Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2011-10-28
Journal Detail:
Title:  Journal of physics. Condensed matter : an Institute of Physics journal     Volume:  23     ISSN:  1361-648X     ISO Abbreviation:  -     Publication Date:  2011 Oct 
Date Detail:
Created Date:  2011-10-31     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  101165248     Medline TA:  J Phys Condens Matter     Country:  -    
Other Details:
Languages:  ENG     Pagination:  455401     Citation Subset:  -    
Virginia Tech Crystallography Laboratory, Department of Geosciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA.
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