Dielectric and tunability properties of La-doped BaTiO3 ceramics

La-doped BaTiO3 (x = 0.001; 0.0025; 0.005; 0.01; 0.025) ceramics were prepared via conventional solid state reaction and sintered at 1300 °C for 6 h, resulting in dense single phase ceramics with homogeneous microstructures. The temperature dependence of dielectric permittivity of the ceramics has been investigated. The results show a decrease of TC with lanthanum addition. The degree of diffuseness of phase transition is more pronounced for high La content, implying the existence of a composition-induced phase transition of the ceramics. The dc-tunability at room temperature was investigated and experimental data were discussed in terms of the Johnson model completed with a Langevin term that describes “extrinsic” contribution to the non-linear ɛ(E) dependences.

► (Ba,La)TiO3 solid solution were prepared via solid state reaction and sintered at 1300 °C/6 h.
► The temperature dependence of permittivity shows a diffuse phase transition with La addition.
► The non-linear properties of the ceramics were investigated at room temperature.
► The experimental data were discussed using the multipolarization mechanism model.