A temperature stable microwave dielectric material Ni^sub 0.35^Zn^sub 0.65^TiNb^sub 2^O^sub 8

A temperature stable, high quality, low sintering temperature microwave dielectric material Ni^sub 0.35^Zn^sub 0.65^TiNb^sub 2^O^sub 8^ was investigated for the first time. The compounds were prepared by a conventional mixed-oxide route and sintered at the temperature range of 1,060-1,140 °C. The microstructure and microwave dielectric properties were investigated systematically. The X-ray diffraction results show that the Ni^sub 0.35^Zn^sub 0.65^TiNb^sub 2^O^sub 8^ ceramics contained two phase: ZnTiNb^sub 2^O^sub 8^ phase and Zn^sub 0.17^Nb^sub 0.33^Ti^sub 0.5^O2 phase. With increase in temperature, the amount of ZnTiNb^sub 2^O^sub 8^ phase decreased and that of Zn^sub 0.17^Nb^sub 0.33^Ti^sub 0.5^O2 increased. The microwave dielectric properties of Ni^sub 0.35^Zn^sub 0.65^TiNb^sub 2^O^sub 8^ were mainly affected by the variation of content and crystal structure of each phase. With increasing temperature, the content of Zn^sub 0.17^Nb^sub 0.33^Ti^sub 0.5^O2 phase increased, resulting in the increasing dielectric constant and τ^sub f^, and decreasing Qf value. In addition, the dielectric constant increased with increasing bulk density, the Qf value were related to the cell volume of each phase, and the τ^sub f^ value had correlation with the bond valence of each phase. Outstanding microwave dielectric properties of [straight epsilon] = 40.9, Qf = 40,870 GHz, especially near-zero τ^sub f^ = 0.62 × 10^sup -6^/°C were obtained sintered at 1,100 °C for 6 h. With the relatively low sintering temperature and excellent dielectric properties in microwave range, this material is very promising for electronic devices application.