Defect mechanisms in high resistivity BaTiO3–Bi(Zn1/2Ti1/2)O3 ceramics

The defect mechanisms that underpin the high energy density dielectric 0.8BaTiO3–0.2Bi(Zn1/2Ti1/2)O3 were investigated. Characterization of the nominally stoichiometric composition revealed the presence of a Ti3+-related defect center, which is correlated with lower resistivities and an electrically heterogeneous microstructure. In compositions with 2 mol. % Ba-deficiency, a barium vacancy-oxygen vacancy pair (VBa−VO), acted as an electron-trapping site. This defect was responsible for a significant change in the transport behavior with a high resistivity and an electrically homogeneous microstructure.