Microwave Dielectric Properties of the (1-x)La2/3TiO3–xLa(Ti1/2Mg1/2)O3 System

(1-x)La2/3TiO3–xLa(Mg1/2Ti1/2)O3 ceramics with x ranging from 0.1 to 0.9 were prepared by conventional solid-state reaction. La2/3TiO3 and La(Mg1/2Ti1/2)O3 were found to form a solid solution over the whole compositional range. However, the second phase La2Ti2O7 existed for x=0.1 and 0.3. As the x value increased from 0.1 to 0.9, the dielectric constant (epsilon)r decreased from 65.1 to 28.4. The oxygen vacancies were the main factor affecting the Q× f values of the (1-x)La2/3TiO3-xLa(Mg1/2Ti1/2)O3 ceramics. A (tau)f value of -5 ppm/°C can be obtained at x=0.3.