Concurrent Optimization of <i>d</i> ₃₃ and <i>Q</i> _m in PZT‐based Ceramics via Defect and Phase‐Boundary Engineering

ABSTRACT Developing high‐performance piezoelectric ceramics that combine both high power‐handling capability and high sensitivity continues to be a crucial challenge, owing to the trade‐off relationship between piezoelectric coefficient ( d 33 ) and mechanical quality factor ( Q m ). In this work, a synergistic strategy of Mn doping and Zr/Ti ratio tuning is proposed to address this challenge in a (Pb 0.955 Sm 0.01 Sr 0.03 )(Zn 0.067 Nb 0.133 Zr 0.42− y Ti 0.38+ y )O 3 ceramic system. First, doping with Mn as an acceptor introduces defect dipoles that pin domain walls, and effectively enhances Q m while decreasing dielectric loss. Afterward, adjusting Zr/Ti ratio alters the crystal structure near the morphotropic phase boundary (MPB), where the tetragonal and rhombohedral phases coexist. These changes can promote polarization rotation and enhance the intrinsic piezoelectric response, mitigating the hardening induced d 33 loss. An optimized composition ( y = 0.010) achieves an outstanding property combination: a high d 33 of ∼508 pC/N, a high Q m of ∼680, a high Curie temperature of ∼282°C, and excellent thermal stability. The associated corresponding ultrasonic transducer exhibits excellent signal sensitivity and thermal reliability. This work demonstrates that synergistic defect and phase‐boundary engineering provides an effective route to designing lead‐based piezoceramics with well‐balanced properties for demanding high‐power applications.