Effect of Ce3+doping on phase and microwave dielectric properties of 0.94MgTiO3−0.06(Ca0.8Sr0.2)TiO3ceramics

Abstract In this study, 0.94Mg (1‐3 x /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.