La2O3 modified 0.4(Ba0.8Ca0.2)TiO3–0.6Bi(Mg0.5Ti0.5)O3 ceramics for high-temperature capacitor applications

La2O3 modified 0.4Ba0.8Ca0.2TiO3–0.6Bi(Mg0.5Ti0.5)O3 were prepared by a conventional mixed oxide route. Single-phase cubic-like perovskite-type X-ray diffraction patterns were observed for all the samples. Dielectric measurements indicated a near-plateau relative permittivity with relaxor behavior for them. Increasing the La2O3 content worsened the relative permittivity at high temperatures. At x=0.15, the near-plateau relative permittivity, 865±85, extended across the temperature range, 50 °C–485 °C. The corresponding loss tangent, tan δ, was ≤0.025 for temperatures between 100 °C and 400 °C. Comparisons of dielectric properties with other materials proposed for high-temperature capacitor applications suggest that 0.4(Ba0.8Ca0.2)(1−x)La2x/3TiO3–0.6Bi(Mg0.5Ti0.5)O3 ceramics are a promising base material for further development.