The effect of the cation substitution on the structural and vibrational properties of Cs_2NaGa_xSc_(1_x)F_6 solid solution

摘要

Raman scattering and x-ray diffration were used to characterize the structural and vibrational properties of the Cs_2NaGa_XSc_(1_x)F_6 solid solutions,for x ranging from 0.0 to 1.0.The Raman spectra,taken at room and low temperature,allow us to follow the phase evolution in detail and indicate the breaking of the local symmetry since low Ga concentration levels.Five compositions were studied by x-ray diffraction:x=0.0,0.2,0.5,0.8,and 1.0.A cubic space group,Fm3m,was found to x=0.0 and x=0.2 and a trigonal one was found to x=0.5,0.8,and 1.0.Details of both phases are presented and the correlation between x-ray diffraction and Raman scattering is discussed.