Microstructures, dielectric and ferroelectric properties of BaHfxTi1−xO3 ceramics

Pure and Hf-doped barium titanate (short for BTO) ceramics were prepared via conventional solid state reaction method. The microstructures, dielectric and ferroelectric properties of BaHfxTi1−xO3 (short for BHT) ceramics with x = 0, 0.1, 0.2, 0.3 and 0.6 have been investigated. The results indicate that Hf4+ ions have entered the unit cell maintaining the perovskite structure of solid solution. It is found that the addition of Hf can restrain grain growth of barium titanate ceramics. As Hf content increases, the Curie temperature of Hf-doped BTO ceramics decreases and the diffuseness of the phase transition of Hf-doped BTO ceramics is enhanced. When temperature is in the range of −35 to 75 °C, the dielectric loss of Hf-doped BTO ceramics is lower than that of the pure BTO ceramics. As Hf content increases, the remnant polarization begins to increase to the maximum and then decreases, while the coercive field gradually decreases.

► The Hf content can reduce the Curie temperature of BTO ceramics, but enhance the diffuseness. ► We present the effect of Hf content on the remnant polarization and coercive field. ► The addition of Hf can inhibit grain growth of barium titanate ceramics.