Role of Bi chemical pressure on electrical properties of BiFeO3–BaTiO3–based ceramics

Effect of Bi non-stoichiometry is one of the big issues in BiFeO3-BaTiO3 (BF-BT) ceramics that have not been resolved clearly. Therefore, 0.65Bi1+xFeO3-0.35BaTiO3 (x = 0–0.06) ceramics were synthesized by a conventional solid-state reaction at different sintering temperatures (TS) to control the Bi non-stoichiometry, which can be varied by the sublimation and/or evaporation of Bi+3 ions during sintering process. The effects of Bi chemical pressure on crystalline phase, microstructure, dielectrics, and piezoelectric properties of BF-BT were evaluated. X-rays diffraction revealed a single perovskite structure with pseudo-cubic symmetry. A prominent enhancement was noticed at x = 0.05 in ferroelectric, dielectric and piezoelectric properties. Typical ferroelectric behaviors were obtained, while unipolar and bipolar strains were enhanced with increasing Bi content. The maximum piezoelectric properties were found at TS = 1000 °C with x = 0.05, having d∗33 = 270 pm/V at 5 kV/mm with Curie Temperature (TC) = 432 °C. [Display omitted] •Single phase 0.65Bi1+xFeO3-0.35BaTiO3 ceramics were successfully synthesized by solid-state reaction and furnace cooling.•Enhanced properties by maximum relative density, uniform and maximum average grain size, and minimum deviation from Bi/Fe=1.•Bi chemical pressure suppressed oxygen vacancy defects which play as a domain wall pinning center and leakage current source.