Microstructure and dielectric properties of BaTiO 3 ceramic doped with yttrium, magnesium, gallium and silicon for AC capacitor application

Abstract The microstructures and dielectric properties of Y-Mg-Ga-Si co-doped barium titanate ceramics were investigated. Y3+ dissolved in the lattice of BaTiO3 replacing both Ba2+ site and Ti4+ site, and Mg2+ replaced Ti4+ site. The replacements of Y3+ and Mg2+ inhibit the grain growth, cause tetragonal-to-pseudocubic phase transition, reduce the dielectric loss, and flatten the temperature dependence of capacitance curve. The incorporation of Ga3+ can improve sintering and increase permittivity. Y3+ and Ga3+ tended to remain close to the grain boundaries, and play an important role as a shell maker in the formation of the core–shell structure in the co-doped BaTiO3 ceramics. Excellent dielectric properties: ϵr = ∼2487, tanδ = ∼0.7% (at 1 kHz), ΔC/C25