Influence of BaO-CaO-SiO<inf>2</inf> on dielectric properties and reliability of BaTiO<inf>3</inf>-based ceramics

The dielectric properties and resistance degradation behavior of BCG-doped BaTiO3-based ceramics were investigated, where BCG consists of BaO, CaO, and SiO2. In oxide ceramics, oxygen vacancies have an important effect on degradation behaviors. X-ray diffraction was employed to analyze the occupancy of Ca2+ in the Ba sites or Ti sites with different BCG contents. For the light-doped, Ca2+ mainly occupy the Ba sites resulting in a decrease of lattice parameters and thus an increase in the enthalpy of reduction which might limit the concentration of oxygen vacancies. However, acceptor defects, Ca Ti which could trap the forming electrons at room temperature but deteriorate the resistance degradation behavior at high temperature, would be generated with excessive BCG contents. Moreover, thermally stimulated depolarization current (TSDC) analysis was carried out to analyze the defect relaxation behavior and the actual concentration. The resistance degradation can be correlated with the depolarization current strength (Jmax) and the relaxation temperature (Tm) versus polarization condition