Dielectric ceramics in the BaO–Sm₂O₃–TiO₂–Ta₂O₅ quaternary system

Dielectric ceramics in the BaO–Sm₂O₃–TiO₂–Ta₂O₅ quaternary system were prepared and characterized for five typical compositions: BaSm₅Ti₇Ta₃O₃₀, Ba₂Sm₄Ti₆Ta₄O₃₀, Ba₃Sm₃Ti₅Ta₅O₃₀, Ba₄Sm₂Ti₄Ta₆O₃₀, and Ba₅SmTi₃Ta₇O₃₀. The latter three compositions tended to form the tungsten–bronze phase, and the ceramics based on these compositions had a high dielectric constant (134–175) and a low dielectric loss (on the order of 10⁻³) but a larger temperature coefficient of the dielectric constant. Meanwhile, the former two compositions generally had a more complex phase constitution, containing the tungsten–bronze phase combined with some unknown phase, and a relatively small temperature coefficient of the dielectric constant in the temperature range of 20 to 85 °C could be achieved in these two compositions.