Breaking the piezoelectricity-coercivity trade-off via local multiphase nanodomain engineering

The pursuit of high-performance piezoelectrics is perpetually constrained by the inherent trade-off between a large piezoelectric coefficient (d₃₃) and a high coercive field (E_C); attaining one usually compromises the other. Here, we demonstrate a novel design strategy—local multiphase nanodomain engineering—to break this inverse relationship. In Eu³⁺-doped Pb(Mg_1/3Nb_2/3)O₃-PbTiO₃ (PMN-PT) relaxor ferroelectric single crystals, we achieve an exceptional combination of a giant d₃₃ of 3100 pC/N and a significantly enhanced E_C. This contrasts with Nd³⁺-doped crystals, which exhibit a higher d₃₃ of 3300 pC/N but a reduced E_C. Through atomic-resolution microscopy, we directly visualize that the smaller Eu³⁺ ion promotes the formation of localized tetragonal (T) nanodomains, which act as pinning sites to increase E_C, while the coexisting rhombohedral (R) and orthorhombic (O) matrices facilitate polarization rotation, enabling high d₃₃. First-principles calculations reveal that the distinct electronic shielding effects of Eu³⁺ and Nd³⁺ dictate the anisotropy of local lattice distortions, steering the formation of different nanodomain structures. Our work transcends conventional doping effects, establishing a foundational strategy for designing advanced ferroelectrics with previously incompatible properties.