Ferroelectric relaxor behaviour Ba_(1-x)A_x(Ti_(0.7)Zr_(0.3))O_3 of and Ba_(1-x)A'_(2x/3) square_(x/3) (Ti_(0.7)Zr_(0.3))O_3 compositions (A = Ca, Sr; A' = Y, La, Bi)

摘要

In order to investigate the effect of A-site homovalent and heterovalent substitution on phase transition in barium titanium zirconium oxide (Ba(Ti_(0.7)Zr_(0.3))O_3), dielectric studies were performed on ceramics of Ba_(1-x)A_x(Ti_(0.7)Zr_(0.3))O_3 and Ba_(1-x)A'_(2x/3)(Ti_(0.7)Zr_(0.3))O_3 compositions (A = Ca, Sr; A' = Y, La, Bi). A preliminary X-ray powder diffraction study has allowed us to determine the limits of solid solution for each composition. A relaxor behaviour appears whatever the value of x in the solid solution domains. The corresponding relaxor characteristics were determined and discussed according to the substituted cation in the twelve coordination number (12-C.N.) crystallographic site. Such new materials are of interest for environmental-friendly applications.