Dependence of microwave dielectric properties on the complex substitution for Ti-site of MgTiO3 ceramics

Effects of the structural characteristics of MgTi0.95(Sn0.05-xZrx)O3 (0 ≤ x ≤ 0.04) and Mg(Ti0.99-xSnx)Zr0.01O3 (0 ≤ x ≤ 0.06) on microwave dielectric properties were investigated. Complete solid solutions consisting of single-phased ilmenite structures with overall compositions of Mg(Ti0.99-xSnx)Zr0.01O3 and MgTi0.95(Sn0.05-xZrx)O3 (x ≤ 0.03) were obtained. However, a secondary phase was detected in MgTi0.95(Sn0.05-xZrx)O3 specimens at x = 0.04. The temperature coefficient of resonant frequency (TCF) of the specimens was affected by distortion of the Ti-site octahedra. The dielectric constants (K) of the specimens were affected by the theoretical dielectric polarizabilities of constituent ions of the ilmenite structure. The quality factor (Qf) was dependent on the Ti-site bond valence, which was a function of the bond strength between the cation and oxygen ion in the oxygen octahedron. The quality factors of MgTi0.95(Sn0.02Zr0.03)O3 and Mg(Ti0.95Sn0.04)Zr0.01O3 improved owing to the well-ordered structure, which was confirmed by analysis of Raman spectra.