Microstructure and dielectric properties of BaTiO3doped with niobium and cobalt

Abstract

The influence of Niobium and Cobalt on the microstructural and dielectric properties of BaTiO₃ with different Ba/Ti ratio was studied. The dopants were coprecipitated over the BaTiO₃ particles. The dopants located at the grain boundaries act as grain inhibitors. On the contrary, the dopants which are incorporated in solid solution produce exaggerated grain growth. The existence of glass-forming impurities in the BaTiO₃ starting powders, favours such a behaviour. A higher size of the starting particles with a stoichiometric ratio Ba/Ti≤1 promotes the obtaining of materials with X7R capacitor characteristics. The increase of the dopant content produces a higher incorporation of the dopant cations on the perovskite lattice, and, a subsequent decrease of the Curie temperature.