Achieving high piezoelectric response and elevated Curie temperature in Sm-modified PMN–PH–PT ceramics: A full-matrix characterization

Abstract

Abstract Pb-based ferroelectric ceramics face a fundamental trade-off between high piezoelectric response (d33) and low Curie temperature (Tc). Here, we demonstrate that combining Sm-doping with a high-Tc PbHfO3 (PH)-based ternary matrix can effectively shift this balance. A series of 0.01Sm-0.2PMN-(0.8−x)PH-xPT ceramics were designed and systematically characterized. A morphotropic phase boundary (MPB) was identified at x ≈ 0.435, where the optimized composition exhibits a high d33 (≈ 830 pC/N) together with an elevated Tc (≈ 256 °C), a combination that lies above the typical d33–Tc trend of Pb-based ferroelectric ceramics. In addition, the ceramic exhibits stable piezoelectric performance up to ~230 °C, indicating excellent thermal stability. A full-matrix electromechanical characterization was performed, yielding a self‑consistent set of elastic, dielectric constants, and piezoelectric coefficients. Compared with a commercial PZT 610HD benchmark, the designed ceramic offers a comparable d33 but a 70 °C higher depolarization temperature. Atomic-resolution TEM reveals heterogeneous local polar configurations in the optimized composition, providing microscopic structural evidence consistent with its excellent piezoelectric performance. This comprehensive property set not only clarifies the intrinsic structure–property relations but also provides a reliable database for high‑temperature piezoelectric device design.