Defect engineering in barium titanate ferroelectric ceramic showing simultaneous enhancement of piezoelectric coefficient and mechanical quality factor

For high-power on-resonant piezoelectric applications, piezoelectric materials with high piezoelectric coefficient (d₃₃) and mechanical quality factor (Q_m) are in high demand. However, previous work has shown that the d₃₃ and Q_m are generally inversely proportional, implying that it is difficult to improve these properties simultaneously. Here we report the simultaneous enhancement of d₃₃ and Q_m in (Mn, Zr) co-doped BaTiO₃ (BT-xMn-yZr) ceramics. Compared with pure BaTiO₃ ceramics, the piezoelectric coefficient (d₃₃) of BT-0.5%Mn-5%Zr ceramic is increased from 190 pC/N to 321 pC/N, and the Q_m is increased from 290 to 513. Furthermore, the Q_m of BT-1%Mn-5%Zr ceramic reaches 1470, and the d₃₃ is 248 pC/N. When both d₃₃ and Q_m are considered, the obtained properties outperform commercial hard Pb(Zr,Ti)O₃ and other typical lead-free ferroelectric ceramics. The experimental results show that the enhanced d₃₃ and Q_m of these ceramics originate from the synergistic effect of defect engineering-induced domain configuration effect and pinning effect. This work provides insights into the design of high-performance high-power lead-free ferroelectric materials.