Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1249653 | Vibrational Spectroscopy | 2010 | 6 Pages |
Abstract
Temperature dependent normal modes and lattice thermal expansion of Sr2Bâ²UO6 (Bâ²Â = 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 â¼1 cmâ1 upon cooling below T* â¼Â 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 Sr2Bâ²UO6 (Bâ²Â = Ni, Co).
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Physical Sciences and Engineering
Chemistry
Analytical Chemistry
Authors
A.F.L. Moreira, A.F. GarcÃa-Flores, E. Granado, N.E. Massa, R.M. Pinacca, J.C. Pedregosa, R.E. Carbonio, A. Muñoz, M.J. MartÃnez-Lope, J.A. Alonso, L. del Campo, D. De Sousa Meneses, P. Echegut,