Enhanced insulating and piezoelectric properties of BiFeO3‐BaTiO3‐Bi0.5Na0.5TiO3 ceramics with high Curie temperature

Abstract BiFeO 3 ‐BaTiO 3 ceramics are promising lead‐free piezoelectric ceramics due to their high piezoelectric properties and high Curie temperature, but their high leakage current density makes the poling difficult. In this study, a decreased leakage current density by three orders of magnitude was obtained in Bi 0.5 Na 0.5 TiO 3 (BNT) added 0.67BiFeO 3 ‐0.33BaTiO 3 (BF‐BT) ceramics. It was found that the largely improved insulating properties benefit from the reduced oxygen vacancies and weak reduction of Fe 3+ to Fe 2+ as confirmed by photoluminescence and X‐ray photoelectron spectroscopy measurements, thereby contributing to high‐temperature and high‐field poling. In addition, the introduction of BNT leaded to increased grain size. Due to the grown grains as well as reduced oxygen vacancies and Fe 2+ , enhanced insulating and optimal piezoelectric properties with P r = 24.2 µC/cm 2 , d 33 = 183 pC/N, k p = 0.28, and T C = 467°C were achieved in BF‐BT‐0.05BNT ceramics.