Raman study of the ordering in Sr(B ` Nb-0.5(0.5))O-3 compounds

Abstract

Strontium based complex perovskites are potential candidates for microwave integrated circuit applications. In the present article, we report on Raman scattering studies of cubic and noncubic structures of Sr((B0.5Nb0.5)-Nb-')O-3 [B'=Ga, In, Y, La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, and Yb] based complex-perovskite materials for an improved understanding of structure-property relations. The spectral results are compared to some tantalum analogues of known crystal structure. The present study reveals a higher degree of ordering for the tantalum compounds compared to those of the niobium analogues. Vibrational studies show a correlation between the tolerance factor and symmetry of these materials. (C) 2000 American Institute of Physics. [S0021-8979(00)10817-5].