Crystal structures and phase transitions in Sr doped Ba{sub 2}InTaO{sub 6} perovskites

• Published in: Journal of solid state chemistry 2013-10, Vol.206
• Main Authors: Zhou, Qingdi, Tan, Teck-Yee, Kennedy, Brendan J., Hester, James R.
• Format: Article
• Language: English
• Subjects: CATIONS; CUBIC LATTICES; DOPED MATERIALS; INDIUM OXIDES; INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; MONOCLINIC LATTICES; NEUTRON DIFFRACTION; PEROVSKITES; PHASE TRANSFORMATIONS; SYNCHROTRONS; X RADIATION; X-RAY DIFFRACTION
• ISSN: 0022-4596; 1095-726X
• DOI: 10.1016/J.JSSC.2013.08.007

The crystal structures of the double perovskites of the type Ba{sub 2−x}Sr{sub x}InTaO{sub 6} have been studied by synchrotron X-ray and neutron powder diffraction methods. The structures are based on ordered array of the tilted InO{sub 6} and TaO{sub 6} octahedra, with the Ba/Sr cations being completely disordered. The structure evolves from cubic to monoclinic Fm3{sup ¯}m→{sup x∼0.6}I4/m→{sup x∼1.2}I2/m→{sup x∼1.6}P2{sub 1}/n. The changes in the symmetry induced by replacing the Ba with Sr have been identified by a symmetry-mode analysis. Variable temperature S-XRD studies of selected examples have shown that heating the samples induces the same sequence of transitions observed in the composition dependent studies. - Graphical abstract: The evolution of the structure of the B-site ordered perovskites has been determined by high resolution powder diffraction. The nature of the transitions are probed by examination of the symmetry-adapted modes. Display Omitted - Highlights: • Synthesis of Ba{sub 2−x}Sr{sub x}InTaO{sub 6} cation ordered perovskites. • Synchrotron X-ray and neutron diffraction structural studies of Ba{sub 2−x}Sr{sub x}InTaO{sub 6}. • Phase transitions in Ba{sub 2−x}Sr{sub x}InTaO{sub 6}. • Symmetry-adapted mode analysis of phase transitions.