Nature of the semiconducting properties of ceramic barium titanate

The compound BaTiO/sub 3/ is a dielectric but can be put into the semiconducting state by means of heat treatment in a reducing atmosphere or by doping with a small (0.1-0.5 mole %) amount of oxides of group-III or group-V elements (so-called donor dopants). The effect of dopants on the properties of barium titanate cannot be explained by means of quasi-chemical reactions. The chemical and crystal-chemical properties of dopant oxides and the phase relations in multicomponent BaTiO/sub 3/-dopant oxides systems make it possible correctly to estimate and predict the dependence of the properties of barium titantate on the dopant oxides.