Dielectric properties of (1-y)Ca1-xLa2x/3TiO3-y(Li,Nd)1/2TiO3 ceramic system at microwave frequency

The solid solution of dielectric ceramic Ca1-xLa2x/3TiO3 system for the composition range of 0.1 ≤ x ≤ 0.9 is studied. The crystal structure of the system is single perovskite. From the X-ray diffraction patterns, the superstructure reflection lines are detected for the composition x ≥ 0.5. With an increase in the substitution amount of La, the permittivity and the temperature coefficient of resonant frequency (TCF) decrease. A maximum Q × f value of 17600 appears at x = 0.4 since that the extrinsic origin for the dielectric loss degrades the Q × f value due to the poor grain growth for the composition x ≥ 0.5. (1-y)Ca1-xLa2x/3TiO3-y(Li,Nd)1/2TiO3 compounds are introduced to obtain a good temperature stability of resonant frequency. With x = 0.4, the composition y = 0.5 shows good temperature stability (τf = +4.5ppm/°C) with a high permittivity of 105 and a Q × f value of 7000 GHz.