Preparation and microwave dielectric properties of CaTiO₃ added Mg_0.95Ni_0.05Ti_0.98Zr_0.02O₃ composite ceramics for high frequency applications

Mg_0.95Ni_0.05Ti_0.98Zr_0.02O₃ and CaTiO₃ were prepared separately using solid state reaction method. The effect of CaTiO₃ addition on the microwave dielectric properties of Mg_0.95Ni_0.05Ti_0.98Zr_0.02O₃ was investigated to get low loss and temperature stable ceramics in (1 – x)Mg_0.95Ni_0.05Ti_0.98Zr_0.02O₃-xCaTiO₃ series. Mg_0.95Ni_0.05Ti_0.98Zr_0.02O₃ formed as the major phase along with Mg_0.95Ni_0.05Ti₂O₅ phase that formed as minor secondary phase for the composition with x = 0. Microwave dielectric properties ∈_r ~ 17.1, Q_uf_o of 195,855 GHz and τ_f of –46.3 ppm/°C were obtained for the composition with x = 0. The positive τ_f value of CaTiO₃, tuned the τ_f value of Mg_0.95Ni_0.05Ti_0.98Zr_0.02O₃ through zero and ∈_r ~ 28.4, Q_uf_o ~ 108,775 GHz and τ_f ~ 3.1 ppm/°C were attained for x = 0.15 in this study. This composition is the best choice for high frequency applications.