Enhanced piezoelectric properties in 0.665PMN–0.335PT-based piezoceramics with high Curie temperature by phase tuning

This study addresses the long-standing challenge of trade-off piezoelectric performance and thermal stability in rare-earth-doped ([Formula: see text]Pb(Mg[Formula: see text]Nb[Formula: see text]O 3 –xPbTiO 3 (PMN–PT) piezoceramics by phase-boundary engineering. Through systematic compositional gradient design, we achieved a breakthrough in PMN–33.5PT–0.01Sm ceramics, yielding a large piezoelectric coefficient ([Formula: see text] [Formula: see text]pC/N) with concurrent high Curie temperature ([Formula: see text]C). This breakthrough resolves the historical [Formula: see text] trade-off in PMN–PT, with the [Formula: see text] representing a 68% improvement over conventional Sm[Formula: see text]-doped PMN–PT, expanding its applicability to mid-temperature applications (100–200 ∘ C) where the original low [Formula: see text] ([Formula: see text]C) of PMN–PT was a bottleneck. Superior piezoelectric coefficient mainly stems from multiphase and local polar nanoregions (LPNRs) coexistence, reducing the energy barrier required for domain switching. Rietveld refinement and transmission electron microscopy (TEM) have identified multiphase and LPNRs coexistence, and LPNRs originate from local composition heterogeneities. This strategy offers a promising material platform for high-temperature piezoelectric applications.