Effect of Sn4+ substitution on microwave dielectric properties of (Mg0.95Ni0.05)(Ti1−Sn )O3 ceramics

Abstract The effects of the substitution of Sn4+ at Ti4+ sites on the structural characteristics and microwave dielectric properties of (Mg0.95Ni0.05)(Ti1 − xSnx)O3 (MNTS, 0 ≤ x ≤ 0.25) ceramics were investigated. Single-phase ilmenite was confirmed up to x = 0.15, and then SnO2 was observed as secondary phase upon further substitution. For the single-phase specimens, the unit-cell volume increased with Sn4+ substitution due to the larger ionic radius of Sn4+ than Ti4+. The quality factor of the MNTS specimens depended on their B-site bond valence. The dielectric constants of the specimens decreased with increasing Sn4+ substitution due to the lower polarizability of Sn4+ compared to Ti4+. The temperature coefficient of the resonant frequency of the specimens decreased with Sn4+ substitution, which could be attributed to the associated decrease in the tolerance factor of the specimens. The relationship between the microstructure and the microwave dielectric properties were also investigated.