Effect of defect dipole-induced aging on the dielectric property of Fe3+-doped Na0.5Bi0.5TiO3 thin film

Na0.5Bi0.5(Ti0.94Fe0.06)O3−δ (NBTFe) thin film was deposited on indium tin oxide coated glass substrate by a metal organic decomposition process. The aging effect on the dielectric properties was mainly studied by the dielectric constant–electric field (εr–E) curves. Obvious aging characteristic of abnormal double butterfly εr–E loops was observed in the NBTFe film. This phenomenon can be attributed to the polarization backswitching behavior under the effect of defect dipoles. Furthermore, the double curve can gradually transform into a typical single one during the course of increasing the applied electric field or decreasing the measuring frequency, which can be explained by the progressively enhanced de-aging effect. These present results are discussed based on defect chemistry by the symmetry-conforming principle of defect dipoles.