Evolution of the dielectric response during the degradation of Mn-doped BaTiO3 ceramics measured by impedance spectroscopy

Summary form only given. The degradation process in sintered materials was examined. Low-frequency dispersion measurements of the dielectric constant were performed during the degradation process, that is by holding the samples under DC field at high temperature while the ε₁(ω) and ε₂(ω) curves were continuously recorded during about one week. The main results were a relative stability of the ε_s-ε_∞ dispersion of ε₁(ω): an increase of ω₂; and the reappearance of the ε₁ anomaly at T_c in the samples sintered under low P_O2. The activation energy obtained from the log ε₁ versus 1/T plot seemed to be incompatible with a displacement of oxygen vacancies