Achieving Giant Piezoelectricity and High Property Uniformity Simultaneously in a Relaxor Ferroelectric Crystal through Rare-Earth Element Doping

Abstract

The low uniformity in properties of relaxor ferroelectric crystals is a long-standing issue in the ferroelectric community, which limits the available volume of the entire crystal boule. The aim of this study is to develop a relaxor ferroelectric crystal with improved property uniformity and excellent piezoelectricity. To this end, Pb(In1/2Nb1/2)O3–Pb(Mg1/3Nb2/3)O3–PbTiO3 is doped with Nd2O3 (Nd–PIN–PMN–PT) to improve the crystal performance. Along the crystal boule, the piezoelectric coefficient d33 varies from 2800 to 3500 pC N−1, and the dielectric constant ranges from 8400 to 9800, with variations of 25% and 16%, respectively. Such high property uniformity results in over 75% available volume of the crystal boule, compared to 30–50% for undoped crystals grown by Bridgman method. At the electric field of 1 kV cm−1, the converse piezoelectric response is up to 4780 pm V−1. In addition, its Curie temperature (TC) and coercive field (EC) are above 150 °C and 3 kV cm−1, respectively. Compared with Pb(Mg1/3Nb2/3)O3–PbTiO3 crystal (d33: 1500 pC N−1, TC: 135 °C, EC: 2.3 kV cm−1), the larger piezoelectricity, the higher TC and EC, and improved uniformity make Nd–PIN–PMN–PT crystals promising candidates for advanced piezoelectric applications.