Please use this identifier to cite or link to this item: http://repositorio.unicamp.br/jspui/handle/REPOSIP/57447
Type: Artigo de periódico
Title: Crystal structure of fluorite-related Ln(3)SbO(7) (Ln=La-Dy) ceramics studied by synchrotron X-ray diffraction and Raman scattering
Author: Siqueira, KPF
Borges, RM
Granado, E
Malard, LM
de Paula, AM
Moreira, RL
Bittar, EM
Dias, A
Abstract: Ln(3)SbO(7) (Ln=La, Pr, Nd, Sm, Eu, Gd, Tb and Dy) ceramics were synthesized by solid-state reaction in optimized conditions of temperature and time to yield single-phase ceramics. The crystal structures of the obtained ceramics were investigated by synchrotron X-ray diffraction, second harmonic generation (SHG) and Raman scattering. All samples exhibited fluorite-type orthorhombic structures with different oxygen arrangements as a function of the ionic radius of the lanthanide metal. For ceramics with the largest ionic radii (La Nd), the ceramics crystallized into the Cmcm space group, while the ceramics with intermediate and smallest ionic radii (Sm Dy) exhibited a different crystal structure belonging to the same space group, described under the Cam setting. The results from SHG and Raman scattering confirmed these settings and ruled out any possibility for the non-centrosymmetric 0221 space group describing the structure of the small ionic radii ceramics, solving a recent controversy in the literature. Besides, the Raman modes for all samples are reported for the first time, showing characteristic features for each group of samples. (C) 2013 Elsevier Inc. All rights reserved.
Subject: Synchrotron X-ray diffraction
SHG
Lanthanide
Antimonates
Raman scattering
Country: EUA
Editor: Academic Press Inc Elsevier Science
Rights: fechado
Identifier DOI: 10.1016/j.jssc.2013.05.001
Date Issue: 2013
Appears in Collections:Unicamp - Artigos e Outros Documentos

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