The enhanced piezoelectricity of 0.7BiFeO3–0.3BaTiO3 by optimizing charge defects through annealing

High-performance 0.7Bi 1.02 FeO 3 –0.3BaTiO 3 ceramics are prepared by traditional solid-state method with annealing. The effect of annealing temperature ( T A ) on the piezoelectric properties of ceramics are revealed by studying the crystal structures, ferroelectric properties, and electrical properties of the as-sintered ceramic and ceramics annealed at 600, 700, 800, and 900 °C. Through the analysis, we found that T A has little influence on the morphology and crystal structure of ceramics, all ceramics are two-phase ( R-PC ) coexistence structures. But T A relates to the concentration of charge defects. When annealing at 800 °C, the charge defects in the ceramic are the least. Therefore the best performance ( d 33  = 202 \(\pm\) 3 pC/N, T C  = 496 °C) ceramic is obtained. Our experiments demonstrate that the charge defects induced by annealing temperature are very important to the piezoelectricity of BFO–BTO ceramics.