Structural variation and microwave dielectric properties of TiO2-doped Ba(Zn1/3Ta2/3)O3 ceramics

The effect of TiO2 on microstructure and microwave dielectric properties of Ba(Zn1/3Ta2/3)O3 (BZT) ceramics was investigated. The addition of TiO2 did not disturb the 1:2 ordering structure of the BZT ceramic. The average grain size significantly increased with the addition of TiO2, which was attributed to the liquid phase formation. A small amount of TiO2 increased the relative density. However, relative density decreased with the addition of the large amount of TiO2 and it might be due to the abnormal grain growth. The Q value of the BZT significantly improved with the addition of the TiO2 for the specimens sintered at 1580 °C and it could be explained by the increased relative density. However, for the specimens sintered at 1630 °C, Q value decreased with the addition of the TiO2 which is attributed to the decrease of the relative density. The maximum Q×f value achieved in this investigation was about 135,000 GHz for the BZT with 1.0 mol.% TiO2 sintered at 1580 °C for 10 h.