Raman and infrared spectroscopy of Sr2B′UO6 (B′ = Ni; Co) double perovskites

Temperature dependent normal modes and lattice thermal expansion of Sr 2B′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, w...

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Detalles Bibliográficos
Autores principales: Moreira, A. F. L., García Flores, A. F., Granados, E., Massa, Néstor Emilio, Pinacca, Rubén Miguel, Pedregosa, José Carmelo, Carbonio, Raul Ernesto, Muñoz, A., Martínez Lope, M. J., Alonso, J. A., Campo, L. del, De Sousa Meneses, D., Echegut, P.
Formato: Articulo Preprint
Lenguaje:Inglés
Publicado: 2010
Materias:
Química
Double perovskites
Infrared reflectivity
Raman scattering
Synchrotron x-ray powder diffraction
Acceso en línea:http://sedici.unlp.edu.ar/handle/10915/95142
https://ri.conicet.gov.ar/11336/67485
Aporte de:
SEDICI (UNLP) de Universidad Nacional de La Plata
Descripción
Sumario:Temperature dependent normal modes and lattice thermal expansion of Sr 2B′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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