The effect of non-stoichiometry on the microstructure and microwave dielectric properties of the Mg_(1+δ)TiO_(3+δ) ceramics

摘要

The microwave dielectric properties and microstructure of Mg_(1+δ)TiO_(3+δ) (-0.05 <=δ <= 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 Qx/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 MgTiO_3 phase, which can be obtained within the compositional range -0.02 < =δ <= 0.02. in addition, a low Q x f measured for specimens at S < -0.02 can be attributed to the presence of second phase MgTi_2O_5. An extremely high Q x f of ～357,600 GHz (at 10 GHz) together with an ε_r of -18.3 and a τ_f of ～-50 ppm/°C can be found for specimen using Mg_(1.02)TiO_(3.02).