Effect of Cobalt Doping on the Structural, Microstructure and Microwave Dielectric Properties of MgTiO3 Ceramics Prepared by Semi Alkoxide Precursor Method



We report a systematic investigation on crystal structure, microstructure, and microwave dielectric properties of (Mg1−xCox)TiO3 (= 0–0.07) ceramics prepared by semialkoxide precursor method. All the as-made samples exhibit an ilmenite structure with an incredible reduction in sintering temperature from 1350°C to 1200°C. Lattice parameter increases with increasing Co content due to the larger ionic radius of Co2+ as compared to Mg2+. The relative density, dielectric constant, and × f0 values increase with increasing Co up to 0.05 and decreases for > 0.05. This is attributed to local lattice distortion, maximum relative density, and uniform grain growth. × f0 values were enhanced from 126 THz for = 0 to a maximum value 170 THz for = 0.05. A best combination of microwave dielectric properties (εr ~ 17.03, × f0 ~ 170 THz @ 9.4 GHz and τf of −40 ppm/°C) was obtained for (Mg0.95Co0.05)TiO3 ceramic sintered at 1200°C for 3 h. The observed results reveal (Mg0.95Co0.05)TiO3 ceramic as one of the promising dielectric materials for low-loss and millimeter-microwave applications.