Effect of the substitution of Bi2O3 on the dielectric properties of barium titanate based ceramics

Barium titanate was A-site substituted by various amounts of bismuth in oxide form assuming both electronic and vacancy compensation. The effect of the bismuth additions on the sintering behaviour, lattice structure and dielectric properties was studied. Special attention was drawn to the temperature dependence of the relative permittivity and the Curie temperature as a function of the amount of Bi added. For the incorporation of 2mol% BiO1.5 to form Ba0.98Bi0.02TiO3 a shift of T-C to lower temperatures (as compared to the Curie temperature of pure barium titanate) was obtained. For higher Bi concentrations most probably compensated by Ba vacancies (according to Ba1-1.5xBixTiO3), a reduced temperature for the maximum value of the permittivity is found along with a simultaneous broadening of the appropriate peak.