Effect of Gd amphoteric substitution on structure and dielectric properties of BaTiO_3-based ceramics

摘要

BaTiO_3-based ceramics (doped with a small amount of Ni~(2+), Mn~(2+), Nb~(5+), Ca~(2+) and Zr~(4+)) with various Gd_2O_3 concentrations were prepared by the conventional solid-state reaction method. Effects of Gd_2O_3 doping concentrations on the structure and dielectric properties were investigated. It was deduced from XRD patterns that different substitution sites of Gd~(3+) ions could be affected by Gd_2O_3 doping amount. Gd~(3+) tended to occupy Ba-site when Gd_2O_3 concentration was less than 0.25 mol%. With increasing Gd_2O_3 doping amount to 0.3 mol%, Gd~(3+) substituted into both Ba- and Ti-site which contributed to an obvious improvement on dielectric constant of BaTiO_3-based ceramics. Influences of the Gd~(3+) amphoteric substitution on the improvement of the dielectric constant were discussed based on the self-compensation mechanism.