In this study, 0.94Mg_(1-3x/2)Ce_xTiO₃−0.06(Ca_0.8Sr_0.2)TiO₃ (MCe_xT−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 Ce³⁺ doping on crystalline phase, microstructure, and microwave dielectric properties of MCe_xT−CST were studied. A main ilmenite (Mg,Ce)TiO₃ phase and a minor perovskite (Ca_0.8Sr_0.2)TiO₃ phase coexist well with the appearance of impurity MgTi₂O₅ phase in MCe_xT−CST. The dielectric properties of MCe_xT−CST are affected by the molecular polarizability, the impurity phase, and the Ce³⁺ doping. The replacement of Mg²⁺ by high valence Ce³⁺ could effectively inhibit the formation of oxygen vacancy, resulting in the enhancement of Q×f. When x = 0.005, MCe_xT−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 Ce³⁺ substitution is a prospective approach to optimize the microwave dielectric properties of MgTiO₃-based ceramics.

中文翻译：

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Ce3+掺杂对0.94MgTiO3−0.06(Ca0.8Sr0.2)TiO3陶瓷相和微波介电性能的影响

本研究在低温下制备了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)复合陶瓷。 1175°C 使用 50 纳米大小的粉末。研究了Ce ^{3+掺杂对MCe} _x T-CST 的晶相、微观结构和微波介电性能的影响。主要钛铁矿(Mg,Ce)TiO ₃相和次要钙钛矿(Ca _0.8 Sr _0.2 )TiO ₃相共存，杂质MgTi _{2出现MCe x} T−CST中的O ₅相。MCe _x T-CST的介电性能受分子极化率、杂质相和Ce ³⁺掺杂的影响。用高价Ce ³⁺代替Mg ²⁺可以有效抑制氧空位的形成，从而提高Q×f。当x  = 0.005 时，MCe _x T-CST 表现出微波介电特性，具有21.5 的中等 εr、67 000 GHz 的高Q ×f_和-0.74 ppm/°C的接近零的τf 。结果表明，Ce ³⁺替代是优化MgTiO ₃基陶瓷的微波介电性能的一种前瞻性方法。