Dielectric tunable properties of high dielectric breakdown Ba0.5Sr0.5TiO3–Zn2P2O7 composite ceramics

Dielectric properties of Ba0.5Sr0.5TiO3–xZn2P2O7 (x = 1, 3, 5, 10, 15 wt%) composite ceramics, which were prepared by solid-state reaction process, were intensively investigated. The results showed that the Curie temperature (Tc) of composites gradually shifted to lower temperature (−140 °C) with increasing the content of Zn2P2O7, and the dielectric constant were tuned effectively from 2020 to 107, while maintaining a relatively high tunability. Zn2P2O7 additions remarkably inhibited the grain growth of Ba0.5Sr0.5TiO3 phases, and improved the breakdown strength of samples up to 385 kV/cm. The sample with x = 10 wt% exhibited good dielectric properties (ɛr = 290, tg δ = 0.0006, T = 20.5%, BDS = 297 kV/cm). Meanwhile Zn2P2O7 addition also made the Tc far away from the room temperature, which reduced the sensitivity of the dielectric constant to temperature change and simultaneously improved the stability of materials.