A low dielectric loss value under large AC electric fields is highly desired for piezoelectric ceramics in high‐power applications. However, only a few reports have focused on studying or revealing the dielectric loss behavior and mechanism of piezoelectric ceramics under an AC electric field. In this work, x (Ca, Fe) co‐doped Pb0.96Sr0.04Zr0.53Ti0.47O3 (x = 0.0, 0.25, 0.5, 1.0, 1.5 mol.%) hard piezoelectric ceramics (PSZT‐xCF) were selected for investigation. The lowest dielectric loss (@ E = 500 V mm−1) was 0.8% at x = 1.5 mol.% after aging for 30 days, which was a decrease by an order of magnitude compared with the counterpart pure PSZT. The origin of ultra‐low dielectric loss was thoroughly analyzed. Combined with Rayleigh's law, we investigated the reason behind the changes in dielectric permittivity under AC electric fields with aging time. The significant reduction in the contribution of extrinsic effect of domain wall motion dominated the reduction in dielectric loss because of the introduction of defect dipoles. This work provides a fundamental understanding of low dielectric loss piezoelectric ceramics under AC electric fields for high‐power applications.

Defect engineering is a proven method to tune the properties of perovskite oxides. In demanding high-power piezoelectric ceramic applications, acceptor doping is the most effective method to harden ceramics, but it inevitably degrades the ceramics' electromechanical properties. Herein, a poling method based on acceptor doping, namely, high-temperature poling, is implemented by applying an electric field above the Curie temperature for poling to achieve a balance of the properties of piezoelectric coefficient d 33 and mechanical quality factor Q m . After high-temperature poling, the piezoelectric property of 0.6 mol % Mn-doped Pb 0.92 Sr 0.08 (Zr 0.533 Ti 0.443 Nb 0.024 )O 3 is d 33 = 483 pC/N and Q m = 448. Compared with the traditional poling, the piezoelectric coefficient d 33 of the high-temperature poling ceramics increased by approximately 40%, and Q m also increased by nearly 18%. Therefore, high d 33 and Q m were exhibited by our PZT piezoelectric ceramics. Rayleigh's law analysis, XRD, and transmission electron microscopy analysis show that, after high-temperature poling, the considerably increased d 33 is related to the large increase in the reversible domain wall motion in the intrinsic effect, while the slightly increased Q m is related to the inhibited irreversible domain wall motion in the extrinsic effect. This study reports a method for high-temperature poling and provides insights into the design of high-power piezoelectric ceramics with high d 33 and Q m . KEYWORDS: PZT, high-temperature poling, defect dipoles, high d 33 and high Q m , high-power applications