Effect of Gd amphoteric substitution on structure and dielectric properties of BaTiO3-based ceramics

BaTiO₃-based ceramics (doped with a small amount of Ni²⁺, Mn²⁺, Nb⁵⁺, Ca²⁺ and Zr⁴⁺) with various Gd₂O₃ concentrations were prepared by the conventional solid-state reaction method. Effects of Gd₂O₃ doping concentrations on the structure and dielectric properties were investigated. It was deduced from XRD patterns that different substitution sites of Gd³⁺ ions could be affected by Gd₂O₃ doping amount. Gd³⁺ tended to occupy Ba-site when Gd₂O₃ concentration was less than 0.25 mol%. With increasing Gd₂O₃ doping amount to 0.3 mol%, Gd³⁺ substituted into both Ba- and Ti-site which contributed to an obvious improvement on dielectric constant of BaTiO₃-based ceramics. Influences of the Gd³⁺ amphoteric substitution on the improvement of the dielectric constant were discussed based on the self-compensation mechanism.