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2010
ACL
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A.F.L.Moreira, A.F.García-Flores, E.Granado, N.E.Massa, R.M.Pinacca, J.C.Pedregosa, R.E.Carbonio, A.Muñoz, M.J.Martínez-Lope, J.A.Alonso, L.del Campo, D.De Sousa Meneses, P.Echegut, 'Raman and Infrared Spectroscopy of Sr2B’UO6 (B’ = Ni, Co)Double Perovskites', Vib. Spectrosc 54 142-147 (2010) doi:10.1016/j.vibspec.2010.08.008
Temperature dependent normal modes and lattice thermal expansion of the Sr2B'UO6 (B' = Ni, Co) double perovskites were investigated by Raman/infrared spectroscopies and synchrotron X-ray diffraction, respectively. Monoclinic crystal structures with space group P21/n were confirmed for both compounds, with no clear structural phase transition between 10 and 400 K. As predicted for this structure, the first-order Raman and infrared spectra show a plethora of active modes. In addition, the Raman spectra reveal an enhancement of the integrated area of an oxygen stretching mode, which is also observed in higher-order Raman modes, and an anomalous softening of ~1 cm-1 upon cooling below T* ~ 300 K. In contrast, the infrared spectra show conventional temperature dependence. The band profile phonon anomalies are possibly related to an unspecified electronic property of Sr2B'UO6 (B' = Ni, Co).
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