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.