Defect mechanisms in high resistivity BaTiO_3-Bi(Zn_(1/2)Ti_(1/2))O_3 ceramics

摘要

The defect mechanisms that underpin the high energy density dielectric 0.8BaTiO_3-0.2Bi(Zn_(1/2)Ti_(1/2)) O_3 were investigated. Characterization of the nominally stoichiometric composition revealed the presence of a Ti~(3+)-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 (V_(Ba) - V_O), 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.