Small-signal piezoelectric properties on Mn-doped BiFeO₃–BaTiO₃ lead-free piezoelectric ceramics

Abstract

Small-signal piezoelectric characteristics in pseudo-cubic BiFeO₃–BaTiO₃-based ceramics are rarely studied. In this study, the xMnO₂-doped 0.67BiFeO₃–0.33BaTiO₃ (BF33BT–xMn, x = 0.0, 0.2, 0.4, and 0.6 wt %) ceramics are investigated. Small and large amounts of Mn ions play different roles in resistivity, with the highest resistivity observed at a MnO₂ content of 0.2 wt %. The examination of poling conditions revealed the impact of electric field strength and poling time on impedance phase θ. The piezoelectric constant (d₃₃) and electromechanical coupling factor (k₃₃) increase with impedance phase θ, while the mechanical quality factor (Q_m) value remains unchanged. Our finding indicates that poled BF33BT–0.2Mn ceramic reaches an impedance phase θ of 73°, k₃₃ of 0.45, Q_m of 41.0, and d₃₃ × Q_m value of 3856 pC/N. This study contributes to further research on the high-power piezoelectric characteristics of lead-free BiFeO₃–BaTiO₃-based ceramics.