Lattice structure and microwave dielectric properties of La[Al 1− x (Mg 0.5 Ti 0.5 ) x ]O 3 ( x = 0‐0.2)‐based ceramics

La[Al 1− x (Mg 0.5 Ti 0.5 ) x ]O 3 (LAMT, x  = 0‐0.2) ceramics were synthesized by the conventional solid‐state reaction method and formed a solid solution. The pure solid solutions were recorded by X‐ray diffraction (XRD) in every range. Relative permittivity ( ε r ) and structural stability were greatly affected because the Al 3+ site was replaced by [Mg 0.5 Ti 0.5 ] 3+ . The total ionic polarizability gradually increased with x , and ε r gradually increased. The trend of τ f is due to the change in structural stability. The variation in Q × f value increased firstly and then decreased due to the change in the symmetric stretching mode of Al/MgTi–O. The optimum microwave dielectric properties of LAMT were obtained at x of 0.1 after sintering at 1650°C for 5 hours, and ε r  = 24.9, Q  ×  f = 79 956 GHz, and τ f  = −33 ppm/°C. The CaTiO 3 have a large positive τ f (+800 ppm/°C), thus, the τ f achieved near zero when CaTiO 3 and LAMT ( x  = 0.1) ceramics were mixed with a certain molar mass, and the optimum microwave dielectric properties of 0.65CaTiO 3 –0.35LaAl 0.9 (Mg 0.5 Ti 0.5 ) 0.1 O 3 were as follows: ε r  = 44.6, Q  ×  f = 32 057 GHz, and τ f  = +2 ppm/°C.