Effects of Y2O3 addition on electrical conductivity and dielectric properties of Ba-excess BaTiO3

When Y3+ ion was substituted for Ti or Ba sites, the electrical conductivity of Ba-excess BaTiO3 showed an acceptor or a donor doped behavior, depending on the Ba/Ti ratio. When Y2O3 was added to Ba-excess BaTiO3 (Ba/(Ti + Y) = 1), the solubility and the primary occupation site of Y3+ ions were estimated from the electrical conductivity behavior. Y2O3 addition to Ba-excess BaTiO3 showed a donor-doped behavior at low levels of Y2O3 (≤1.0 mol%) and an acceptor-doped behavior at higher levels (>1.0 mol%). Grain growth inhibition occurred at 1.0–1.25 mol% Y when the sample was fired at 1300 °C. Effects of Y2O3 addition on electrical conductivity and dielectric characteristics of Ba-excess BaTiO3 were dependent on the site occupancy of Y3+ ion in BaTiO3 lattice.