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 degrees C could be achieved in these two compositions.