Controllable low-temperature flash sintering and giant dielectric performance of (Zn,Ta) co-doped TiO2 ceramics

In this study, the challenge of high-temperature and long-time sintering of (Zn, Ta) co-doped TiO₂ ceramics is solved successfully using flash sintering technology. Joule heating and a high heating rate make the sample compact rapidly at low temperatures (1050 °C in 24 min). When the electric field was equal to 200 V/cm, high permittivity (ε' ～ 1.32 × 10⁴), low dielectric loss tangent (tan δ ～ 0.27), and nonlinear coefficient ($\alpha$ ～ 5.8) values were obtained. Flash sintered samples have more free electrons, resulting in a high dielectric constant. Further, the higher the electric field, the smaller the grain resistance of the sample; this condition is conducive to reducing dielectric loss. giant dielectric performance is explained by the combined action of the electron-pinned defect dipole theory and the internal barrier layer capacitance effect. Therefore, this study provides a promising prospect for the green preparation of co-doped TiO₂ giant dielectric ceramics.