Role of niobium in magnesium titanate microwave dielectric ceramics

The effect of niobium doping on MgTiO3 ceramics was evaluated in terms of microstructure and microwave dielectric properties, Pure and doped MgTiO3 dense ceramics mere produced, Doping levels of niobium were 0.5, 1, and 2 at.% of Nb5+. Phase assemblages were examined by XRD and checked by EDS during microstructural observations by SEM, Microwave dielectric properties were measured at 8 GHz, Dielectric permittivity was not much affected by doping, Q decreased for the sample with the higher Nb content because of the presence of a second phase, For low Nb contents, a solid solution was formed and Q even increased, An explanation is presented based on the elimination of lattice defects.