Microwave Dielectric Properties of (A2+1/3 B5+2/3)0.5Ti0.5O2 (A2+=Zn, Mg, B5+=Nb, Ta) Ceramics

Dielectric properties of (A²⁺ _1/3B⁵⁺ _2/3)_0.5Ti_0.5O₂ (A=Zn²⁺, Mg, B⁵⁺=Nb, Ta) ceramics were investigated at microwave frequencies. Dielectric properties were strongly dependent on the structural characteristics and cooling rate. The specimens with Nb⁵⁺ showed larger dielectric constant (K) than those with Ta⁵⁺ due to the decrease of bond valence. Quality factor (Qf) of the specimens was dependent on the reduction of Ti⁴⁺ ion as well as microstructure. Temperature coefficients of the resonant frequencies (TCF) of the specimens with Nb⁵⁺ were larger than those with Ta⁵⁺. These results could be attributed to the changes of oxygen octahedral distortion.