Effect of A/B ratio on the dielectric properties and insulation resistance of barium titanate sintered in a reducing atmosphere

•A/B ratios impact barium titanate's dielectric properties.•A/B ratio of 1.002 enhances resistivity and insulation.•Oxygen vacancy and Ti3+/Ti4+ ratios vary with A/B.•Study aids in improving MLCC reliability and performance. The effect of the A/B ratio on the dielectric properties and insulation resistance of barium titanate (BaTiO3) sintered in a reducing atmosphere was investigated in this study. The increased demand for high capacitance, miniaturized, and reliable base metal electrode multilayer ceramic capacitors (BME MLCCs) has emphasized improving insulation properties. This study added Y2O3, MgO, Mn2O3, and SiO2 to tailor the barium titanate properties. We investigated how changes in the A/B ratio affect the microstructure, defect chemistry, and Y3+ ion occupation in BaTiO3, affecting dielectric properties and insulation resistance. It was observed that the activation energies for grain and grain boundary conductivity are dominated by oxygen vacancy and (VBa″−VO··) defect pair, respectively. The Ti3+ and oxygen vacancy concentrations were directly proportional to the room and high-temperature resistivities, respectively. The sample with an A/B ratio of 1.002 had the lowest oxygen vacancy and Ti3+ ratio, resulting in a higher resistance and lower thermally stimulated depolarization current (TSDC). Thermally stimulated depolarization current results of the samples with varying A/B ratios. [Display omitted]