X-ray diffraction and Raman spectroscopy studies of temperature and composition induced phase transitions in Ba_{2鈭?span style='font-style: italic'>x}Sr_xZnWO₆ (0 鈮?#xa0;x 鈮?#xa0;2) double perovskite oxides

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• 作者：Bouchaib Manoun^a ; ^{manounb@gmail.com} ; A. Ezzahi^a ; S. Benmokhtar^b ; A. Ider^a ; P. Lazor^c ; L. Bih^d ; J.M. Igartua^e
• 关键词：Ba2&minus ; xSrxZnWO6 double perovskite oxides ; Phase transition ; Rietveld refinements ; High temperature Raman spectroscopy
• 刊名：Journal of Alloys and Compounds
• 出版年：2012
• 期刊代码：45_09258388
• 类别：ms
• 出版时间：25 August, 2012
• 卷：533
• 期：Complete
• 页码：43-52
• 文件大小：1556 K

摘要

X-ray diffraction and Raman spectroscopy studies of Sr doped double perovskites compound Ba_2鈭?em>xSr_xZnWO₆ with (0&#xA0;鈮?#xA0;x&#xA0;鈮?#xA0;2) were investigated. As a function of composition while increasing strontium amount, the samples show two phase transitions from cubic to tetragonal phase and from tetragonal to monoclinic structure. Both Rietveld refinements and Raman studies showed that the first phase transition occurs between x&#xA0;=&#xA0;1 and 1.2; the second phase transition is observed around x&#xA0;=&#xA0;2. Furthermore, increasing the temperature for the compositions (1.2&#xA0;鈮?#xA0;x&#xA0;<&#xA0;2), manifests the tetragonal to cubic phase transition. For x&#xA0;=&#xA0;2 two phase transitions were observed as a function of temperature. For this series, the phase transitions are illustrated by considerable changes in the composition and temperature dependence of the modes. All the Raman modes show a linear behavior when the composition or temperature is increased, then the slope change indicating the symmetry change.