Structures and phase transitions in Sr1−xBaxHfO3perovskites

Autor: Richard Garrett, Brendan J. Kennedy, Kenichi Kato, Yoshiki Kubota, Leqing Li
Rok vydání: 2004
Předmět:
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