Impact of the change in charge compensation mechanism on the electrical, dielectric, and structural properties of La-doped BaTiO3 ceramics

Abstract

La-doped BaTiO3 ceramics are essential materials in electronic devices, finding applications in multilayer ceramic capacitors and positive temperature coefficient thermistors. While the electrical properties of La-doped BaTiO3 have been investigated, the impact of its room-temperature resistivity anomaly on dielectric properties remains unclear. We synthesized pristine and La-doped BaTiO3 (0.1 - 0.5 mol%) powders via hydrothermal methods, and then sintered bulk samples. Their resistivities (DC and AC), Curie temperature, room-temperature dielectric constant, and lattice volume with varying La doping concentrations were characterized. Beyond 0.3 mol%, the shift from electronic to ionic charge compensation mechanisms resulted in abrupt changes in resistivities, Curie temperature, and dielectric constant near 0.3 mol%. Given minimal changes in average grain size and relative density near 0.3 mol% La, the dominant factor influencing the dielectric constant peaking near this concentration was the shift in charge compensation mechanism.