Structures and phase transitions in Sr1−xBaxHfO3perovskites
Autor: | Richard Garrett, Brendan J. Kennedy, Kenichi Kato, Yoshiki Kubota, Leqing Li |
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Rok vydání: | 2004 |
Předmět: |
Diffraction
Phase transition Materials science biology Condensed matter physics Superlattice Bragg's law Synchrotron radiation General Chemistry biology.organism_classification Condensed Matter::Materials Science Materials Chemistry Condensed Matter::Strongly Correlated Electrons Orthorhombic crystal system Imma Perovskite (structure) |
Zdroj: | J. Mater. Chem.. 14:263-273 |
ISSN: | 1364-5501 0959-9428 |
DOI: | 10.1039/b308258j |
Popis: | Variable temperature synchrotron powder diffraction methods have been used to study the structures and phase transitions in a series of perovskites of composition Sr1−xBaxHfO3. We find that increasing the Ba content results in a transition from the orthorhombic Pnma type structure to the cubic Pmmvia two intermediate phases, Imma and I4/mcm, as follows:The identification of the correct symmetry has relied on a combination of the observed splitting of the main Bragg reflections and the systematic absence of weak superlattice reflections. Variable temperature diffraction measurements have been used to establish the nature of the various phase transitions (continuous or first order) and these generally are consistent with group theoretical analysis. Unusual behavior is observed for the two compositions Sr0.5Ba0.5HfO3 and Sr0.8Ba2HfO3 at low temperatures. |
Databáze: | OpenAIRE |
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