Realizing the balanced optimization between the low hysteresis and superior temperature stability for the electrostrain response in PT-based ferroelectric ceramics

Current research on optimizing the electrostrain response of piezoceramics indicates that, although strain value has consistently been broken through, ensuring low hysteresis along with good thermal stability remains a challenge. In this work, the piezoelectric and ferroelectric properties of PST-xPT ceramics near MPB, as well as their electrostrain response, are systematically investigated. The maximum d₃₃ (680pC/N) and k_p (0.70) were obtained at x = 0.44, owing to the highest P_r and ε_r resulting from the coexistence of R and T phases. The maximum unipolar strain (S_uni) with ultra-low hysteresis (8 %) was achieved at x = 0.46, the result of increased intrinsic lattice distortion and decreased extrinsic domain wall motion with rising PT content. The piezoelectric strain coefficient (d₃₃*) remained almost unchanged in the temperature range of 25 °C to 100 °C. Across various temperatures, the bipolar strain consistently follows the same S_bipolar-E trajectory as the electric field increases from 0 to 4 kV/mm in 0.05 kV/mm increments, demonstrating excellent temperature stability, which is attributed to the synergistic effect of increased dielectric permittivity (ε_r) and decreased remnant polarization (P_r). Therefore, PST-xPT ceramics, exhibiting the strain response with ultra-low hysteresis and excellent temperature stability, are anticipated to be applied in high-performance precise actuators.