Crystal structures and phonon modes of Ba(Ca1/2W1/2)O3, Ba(Ca1/2Mo1/2)O3 and Ba(Sr1/2W1/2)O3 complex perovskites investigated by Raman scattering

被引：8

作者：

Dias, Anderson ^{[1
]}

Siqueira, Kisla P. F. ^{[1
]}

Moreira, Roberto L. ^{[2
]}

机构：

[1] Univ Fed Ouro Preto, Dept Quim, BR-35400000 Ouro Preto, MG, Brazil

[2] Univ Fed Minas Gerais, Dept Fis, BR-30123970 Belo Horizonte, MG, Brazil

来源：

JOURNAL OF RAMAN SPECTROSCOPY | 2010年 / 41卷 / 01期

关键词：

double perovskites; Raman spectroscopy; ceramics; microwave dielectrics; crystal structure; MICROWAVE DIELECTRIC-PROPERTIES; CERAMICS; DIFFRACTION; TUNGSTATES; RESONATORS; BA2SRWO6; FILTERS; SR; TE;

D O I：

10.1002/jrs.2399

中图分类号：

O433 [光谱学];

学科分类号：

0703 ; 070302 ;

摘要：

This work investigates the crystal structures and phonon modes of Ba(Ca1/2W1/2)O-3, Ba(Ca1/2Mo1/2)O-3 and Ba(Sr1/2W1/2)O-3 perovskites by Raman spectroscopy. The samples were produced by conventional solid-state processing at 1200 degrees C. X-ray diffraction showed that single-phase homogeneous materials were produced, which are cubic or pseudo-cubic in symmetry. The existing controversies in the literature for these complex perovskites were investigated by comparing experimental Raman data with group-theory analysis. Ceramics with Ca and W or Mo were found to be cubic, space group Fm (3) over barm. For these materials, four Raman-active bands were observed and the fitting parameters showed that the Ba(Ca1/2Mo1/2)O-3 ceramic presents bands at lower wavenumbers if compared with the Ba(Ca1/2W1/2)O-3 sample. For the Ba(Sr1/2W1/2)O-3 material, two hypotheses were investigated for monoclinic or triclinic structures. The experimental results showed 12 Raman-active modes for this ceramic, which is in perfect agreement with the theoretical predictions for a monoclinic (I2/m) structure. Copyright (C) 2009 John Wiley & Sons, Ltd.

引用

页码：93 / 97

页数：5

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