Temperature and composition induced phase transitions in Sr2-xCa1+xTeO6 (0 <= x <= 2) double perovskite oxides
2017 (English)In: Journal of Molecular Structure, ISSN 0022-2860, E-ISSN 1872-8014, Vol. 1131, 103-113 p.Article in journal (Refereed) Published
Structures of Sr2-xCa1+xTeO6 double perovskites have been studied by the profile analysis of X-ray diffraction data and Raman spectroscopy at room temperature. This series adopts a monoclinic symmetry for the compositions (0 <= x <= 0.5) with P2(1)/n as space group and a triclinic system with P (1) over bar space group for the compositions (0.5 < x <= 2). These results were confirmed by the observed tolerance factor calculated from the distances obtained from the Rietveld refinements which indicates that the true tilt system for the compositions range (0.5 < x <= 2) is the triclinic tilt system. Clear changes in the Raman modes centered at 600, 610 and 620 cm(-1) and the FWHM of O-Te-O bending vibrations, centered at 738 cm(-1) confirmed that the triclinic symmetry takes place between the compositions x = 0.5 and x = 1. Furthermore, Raman spectroscopy studies at high temperature were done for Ca3TeO6. For this compound, considerable changes in the temperature dependence of the modes were well illustrated.
Place, publisher, year, edition, pages
2017. Vol. 1131, 103-113 p.
Inorganic compounds, X-ray diffraction, Raman spectroscopy, Crystal structure, Phase transition
IdentifiersURN: urn:nbn:se:uu:diva-316406DOI: 10.1016/j.molstruc.2016.11.036ISI: 000392683600012OAI: oai:DiVA.org:uu-316406DiVA: diva2:1078090
FunderSwedish Research Council, 348- 2014-4287