Oil acid-assisted lanthanum ions doping by hydrothermal synthesis for boosting dielectric property of BaTiO3 ceramics

To meet the growing demands for smaller, thinner, and higher-capacity multilayer ceramic capacitors (MLCCs), there is a significant need for high-quality, fine nanopowders. Herein, the fine lanthanum doping barium titanate (BLT) metastable nanopowders were hydrothermally prepared by a simple oil acid-assisted lanthanum ions doping strategy. Due to the initially adsorption between Ti⁴⁺ ions and oleic acid molecules, Ba²⁺ ions grow in situ on tetrabutyl titanate, resulting in the formation of fine barium titanate particles (30–60 nm). Upon introducing lanthanum ions, the obtained BLT ceramics (5 mol%) displayed an maximum dielectric constant (Dc_max, 7746 F/m) with a low dielectric loss of 0.05796 under 180 °C, which is 270 % higher than that of pure BT ceramics. The boosted dielectric constant can be attributed to the fact that the uneven substitution of lanthanum for barium cations, which creates numerous titanium vacancies to promote spontaneous polarization. This study offers a reliable approach for producing high-dielectric tetragonal BLT ceramics.