The effect of non-stoichiometry on the microstructure and microwave dielectric properties of the Mg1+δTiO3+δ ceramics

The microwave dielectric properties and microstructure of Mg1+delta TiO3+delta (-0.05 <= delta <= 0.05) ceramics prepared via the conventional solid-state route were investigated. A slight deviation from stoichiometry does not practically affect the relative permittivity and temperature coefficient of resonant frequency of the specimen. However, the Q x f value is very sensitive to the composition and it shows a non-linear variation corresponding to a relative amount of Mg. A very high Q x f can be achieved for specimen with single MgTiO3 phase, which can be obtained within the compositional range -0.02 <= delta <= 0.02. In addition, a low Q x f measured for specimens at delta < -0.02 can be attributed to the presence of second phase MgTi2O5. An extremely high Q x f of similar to 357,600 GHz (at 10 GHz) together with an epsilon(r) of similar to 18.3 and a tau(f) of similar to-50 ppm/degrees C can be found for specimen using Mg1.02TiO3.02. (C) 2011 Elsevier B.V. All rights reserved.