Low electric field induced large electromechanical properties of BiFeO3-BaTiO3-based ceramics via phase composition modulation

The development of high-temperature lead-free piezoelectric ceramics with excellent electromechanical properties under low field remains a key challenge. A series of 0.995(xBiFeO3-(1-x)BaTiO3)-0.005Bi(Zn0.5Hf0.5)O3 ceramics were designed via modulating phase composition. The excellent electromechanical properties of d33* = 511 pm/V (45 kV/cm) at room temperature and S = 0.476 % (d33* = 1190 pm/V, 40 kV/cm) at 120 ℃ were achieved in the x = 0.67 ceramic owing to the synergistic contribution of phase composition and domain evolution. The XRD results verify that the x = 0.67 ceramic is dominated by the pseudocubic phase. The PFM results in the x = 0.67 and 0.71 ceramics confirm that the domain structures consist of nanodomains with strong and weak piezoelectric responses. More importantly, the temperature and voltage-dependent domain evolution testify the nanodomains are easier to switch in the x = 0.67 ceramic. This work provides a strategy to optimize the electromechanical performance at the low field and a deeper understanding of BF-BT-based piezoceramics.