Simultaneously achieving giant piezoelectricity and record coercive field enhancement in relaxor-based ferroelectric crystals

A large coercive field (E-C) and ultrahigh piezoelectricity are essential for ferroelectrics used in high-drive electromechanical applications. The discovery of relaxor-PbTiO3 crystals is a recent breakthrough; they currently afford the highest piezoelectricity, but usually with a low E-C. Such performance deterioration occurs because high piezoelectricity is interlinked with an easy polarization rotation, subsequently favoring a dipole switch under small fields. Therefore, the search for ferroelectrics with both a large E-C and ultrahigh piezoelectricity has become an imminent challenge. Herein, ternary Pb(Sc1/2Nb1/2)O-3-Pb(Mg1/3Nb2/3)O-3-PbTiO3 crystals are reported, wherein the dispersed local heterogeneity comprises abundant tetragonal phases, affording a E-C of 8.2 kV/cm (greater than that of Pb(Mg1/3Nb2/3)O-3-PbTiO3 by a factor of three) and ultrahigh piezoelectricity (d(33) = 2630 pC/N; d(15) = 490 pC/N). The observed E-C enhancement is the largest reported for ultrahigh-piezoelectric materials, providing a simple, practical, and universal route for improving functionalities in ferroelectrics with an atomic-level understanding. High-drive electromechanical applications require ferroelectrics accounting for a large coercive field and high piezoelectricity simultaneously but it is still a challenge. Here, the authors demonstrate it in a relaxor-based ferroelectric crystal.