Dielectric properties of La-substituted Pb_0.5Ca_0.5[(Mg_1/3Nb_2/3)_0.5Ti_0.5]O₃ ceramics

Modification of Pb_0.5Ca_0.5[(Mg_1/3Nb_2/3)_0.5Ti_0.5]O₃ dielectric ceramics was performed by up to 20 mol% La substitution for Pb and Ca. The temperature coefficient of dielectric constant was significantly reduced by the present approach, while an increased Qf factor was achieved. Good microwave dielectric properties were obtained in a composition Pb_0.425Ca_0.425La_0.1[(Mg_1/3Nb_2/3)_0.5Ti_0.5]O₃: ε = 125; Qf = 3150 GHz; calculated temperature coefficient of resonant frequency δ_f = +253 ppm/°C.