Effect of Ce³⁺doping on phase and microwave dielectric properties of 0.94MgTiO₃−0.06(Ca_0.8Sr_0.2)TiO₃ceramics

Abstract

In this study, 0.94Mg (1-3x/2) Ce x TiO 3 −0.06(Ca 0.8 Sr 0.2 )TiO 3 (MCe x T−CST, 0≤x≤0.01) composite ceramics were prepared at a low temperature of 1175 • C by using the 50-nm-sized powders. The effects of Ce 3+ doping on crystalline phase, microstructure, and microwave dielectric properties of MCe x T−CST were studied. A main ilmenite (Mg,Ce)TiO 3 phase and a minor perovskite (Ca 0.8 Sr 0.2 )TiO 3 phase coexist well with the appearance of impurity MgTi 2 O 5 phase in MCe x T−CST. The dielectric properties of MCe x T−CST are affected by the molecular polarizability, the impurity phase, and the Ce 3+ doping. The replacement of Mg 2+ by high valence Ce 3+ could effectively inhibit the formation of oxygen vacancy, resulting in the enhancement of Q×f. When x = 0.005, MCe x T−CST exhibits microwave dielectric properties with a moderate ε r of 21.5, a high Q×f of 67 000 GHz, and a near-zero τ f of −0.74 ppm/ • C. The results reveal that the Ce 3+ substitution is a prospective approach to optimize the microwave dielectric properties of MgTiO 3 -based ceramics. K E Y W O R D S0.94Mg (1-3x/2) Ce x TiO 3 −0.06(Ca 0.8 Sr 0.2 )TiO 3 , Ce 3+ doping, low-temperature sintering, microwave dielectric properties 1 3392