Synthesis of BaZr0.75Hf0.25O3 by a solid-state reaction technique and characterizations of dielectric properties

High phase purity BaZr0.75Hf0.25O3 (BZH) powders were synthesized from a solid-state reaction using stoichiometric BaCO3 (98%), ZrO2 (98.5%), and HfO2 (98%) powders. The probable reaction pathways were elucidated employing simultaneous thermogravimetry analysis and differential scanning calorimetry (TGA and DSC). The phase variations in compounds heated at different temperatures were also analyzed by X-ray diffraction (XRD). The microstructures and composition of the powders and ceramics were measured and confirmed by TEM and SEM. The dielectric constant was greatly suppressed and low loss was obtained under a dc electric field. At the temperature range of -200 ∼ 120 deg. C, the tunability and the figure of merit (K) are 15.5 ∼ 17% and 35 ∼ 55, respectively