Enhanced electromechanical performance of PSZT–PMS–PFW through morphotropic phase boundary design and defect engineering

Abstract

It is desirable but challenging to explore piezoelectric ceramics with high mechanical quality factor Q_m and large mechanical piezoelectric coefficient d₃₃ simultaneously because of the intrinsic restriction between d₃₃ and high Q_m. This work combines morphotropic phase boundary (MPB) with defect engineering to solve the above problem. It not only achieves low energy barriers between polar states near MPB but also introduces oxygen vacancy suppressing the movement of domain walls. Guided by theoretical design, we synthesize PbFe_2/3W_1/3O₃ doped Pb_0.95Sr_0.05Zr_0.52Ti_0.48O₃–PbMn_1/3Sb_2/3O₃ ceramics. As a classical relaxor dopant, PbFe_2/3W_1/3O₃ tends to change the local structure of Pb-based perovskite ferroelectrics and introduces multiply charged defect dipoles. Excellent comprehensive piezoelectric performance with a large d₃₃ of ∼390 pC N⁻¹ and a high Q_m value of ∼1000 is obtained in the Pb_0.95Sr_0.05Zr_0.52Ti_0.48O₃–PbMn_1/3Sb_2/3O₃–PbFe_2/3W_1/3O₃ ternary system. Moreover, the d₃₃ value increases by over 60% while the Q_m remains almost unchanged as compared to the properties of the undoped 0.9Pb_0.95Sr_0.05Zr_0.52Ti_0.48O₃–0.1PbMn_1/3Sb_2/3O₃ ceramic. By Rietveld structural refinement of X-ray powder diffraction, piezoresponse force microscopy, and X-ray photoelectron spectroscopy, it is demonstrated that the excellent piezoelectric performance should be ascribed to the formation of nanoscaled inhomogeneous microstructures resulting from the morphotropic phase boundary and the unchanged Q_m value should be attributed to the inhibition of the movement of domain walls resulting from defect dipoles. Our research provides a novel idea for developing piezoelectric ceramics with high d₃₃ and large Q_m by combining MPB with defect engineering. It is expected to benefit a wide range of high-power piezoelectric ceramics.