Microstructure and electrical properties of Tb-doped zinc oxide-based ceramics

The microstructure and electrical properties of Zn–Pr–Co–Cr–Tb oxide-based ceramics were investigated for different Tb4O7 amounts. The increase of Tb4O7 amount led to more densified ceramics, increasing from 5.73 to 5.85 g/cm3 in sintered density. The average grain size decreased from 13.1 to 5.0 μm with the increase of Tb4O7 amount. It increased in the range of 8.9–42.0 in the nonlinear coefficient and in the range of 1026–6514 V/cm in the breakdown field. The highest nonlinear coefficient (42) was obtained for 1.0 mol% Tb4O7. As Tb4O7 amount increased, the donor density decreased in the range of 1.23 × 1018–0.70 × 1018/cm3, whereas the barrier height at grain boundaries increased in the range of 0.73–0.93 eV.