Substitution preference and dielectric properties of Y 3+-doped Ba 0.62Sr 0.38TiO 3 ceramics

Abstract

Ba 0.62Sr 0.38TiO 3 ceramics of perovskite structure are prepared by solid reaction method with addition of x mol% Y 3+ and their dielectric properties are investigated systematically. It is found that, integrating with the lattice parameters and the distortion of crystal lattice, there is an alternation of substitution preference of Y 3+ ion for the host cations in perovskite lattice. Owing to Y 3+ ion entering the A site, the highest dielectric constant is 5300 for 0.5 mol%-Y 3+-doped samples; when the Y 3+ ion content is more than 0.5 mol%, Y 3+ ion tends to occupy the B site in perovskite lattice, causing a drop of the dielectric constant. Owing to appearance of the oxygen vacancy and disappearance of the reduction of Ti 4+ ion, the optimized dissipation factor is 0.0015 for 1.0 mol%-Y 3+-doped samples, and the dissipation factor is very stable with the environment temperature increasing, making it a superior candidate material for applications. It is also found that the clear deviations from Curie–Weiss law can be seen in various yttrium-doping specimens, revealing the diffuse phase transition.