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

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(In(1/2)Nb(1/2))O(3)–Pb(Mg(1/3)Nb(2/3))O(3)–PbTiO(3) is doped with Nd(2)O(3) (Nd–PIN–PMN–PT) to improve the crystal performance. Along the crystal boule, the piezoelectric coefficient d (33) 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 (T (C)) and coercive field (E (C)) are above 150 °C and 3 kV cm(−1), respectively. Compared with Pb(Mg(1/3)Nb(2/3))O(3)–PbTiO(3) crystal (d (33): 1500 pC N(−1), T (C): 135 °C, E (C): 2.3 kV cm(−1)), the larger piezoelectricity, the higher T (C) and E (C), and improved uniformity make Nd–PIN–PMN–PT crystals promising candidates for advanced piezoelectric applications.