Vibrational spectroscopy study of Ba2-xSrxMgMoO6 Rachid Abkar1, Bouchaib Manoun1,A.Hachimi1 , A. Elaamrani1 S. Benmokhtar2 and P. Lazor3 1

Laboratoire des Sciences des Matériaux, des Milieux et de la modélisation (LS3M), FPK Khouribga, Université Hassan 1er, Morocco. 2 LRCPGM, Laboratoire de Recherche de Chimie-Physique Générale des Matériaux, Département de Chimie, Faculté des Sciences Ben M’Sik Casablanca, Maroc 3 Department of Earth Sciences, Uppsala University, SE-752 36, Uppsala, Sweden Corresponding author email: [email protected] Keywords: Double perovskite, Phase transition, Raman spectroscopy, X-ray diffraction, Ba2xSrxMgMoO6

Double perovskite oxides of the type A2MM’O6, where A is an alkaline earth cation and M and M’ are two heterovalent transition-metal elements show a large variety of physical and chemical properties. Because of the important applications of the double perovskites in diverse fields including ferroelectrics, superconductivity [1-3], colossal magnetoresistance effects, such as CMR discovery in Sr2FeMoO6 and ionic conductors [4-5]. Oxides with the perovskite structure in modern materials continue to grow. To contribute to a better investigation to follow structural phases transition in this type of compounds, we have undertaken the synthesis by solid state method of large number of oxides Ba2-xSrxMgMoO6

(0 ≤ x ≤ 2)

using X-ray diffraction and Raman spectroscopy

techniques. We report in this work on the effect of Sr substitution at the A-site and on the high temperature induced phase transition in Ba2-xSrxMgMoO6 (0 ≤ x ≤ 2). Their crystal structure was solved by Rietveld refinement of X-ray powder diffraction patterns. The study with high-temperature Raman spectroscopy showed the phase transition from the cubic phase to tetragonal phase and thus confirming the X-ray diffraction results. References: [1] R.E. Newnham, G.R. Ruschau, J. Am. Ceram. Soc. 74 (1991) 463. [2] R.J. Cava, R.B. van Dover, B. Batlogg, E.A. Rietman, Phys. Rev. Lett. 58 (1987) 408. [3] J.J. Capponi, C. Chaillout, et al., Europhys. Lett. 3 (1987) 1301. [4] G.Q. Gong, C. Canedy, G. Xiao, et al., Appl. Phys. Lett. 67 (1995) 1783. [5] K. Ramesha, V. Thangadurai, D. Sutar, et al., Mater. Res. Bull. 35 (2000) 559.