Dielectric and piezoelectric properties of high curie temperature single crystals in the Pb(Yb_1/2Nb_1/2)O₃-xPbTiO₃ solid solution series

Piezoelectric single crystals in the (1-x)Pb(Yb_1/2Nb_1/2)O₃-xPbTiO₃ (PYN-xPT) solid solution series were grown by a conventional high temperature solution method using PbO flux. The Curie temperature for compositions grown near the morphotropic phase boundary (x = 0.5) was in the range from 300 to 400°C due to compositional variations and the addition of 1 mol% Ba²⁺, added for perovskite stability. With increasing PT content, the dielectric properties continuously changed from relaxor to normal ferroelectric behavior in the range of 0.2 < x < 0.8. The coercive field (E_c) for rhombohedral crystals near the MPB was 10-15 kV/cm, increasing to 20kV/cm for the tetragonal crystals. The remnant polarization (P_r) also increased with the increasing of PT content from 0.9 μC/cm² (x = 0.2) to 42 μC/cm² (x = 0.53). The piezoelectric coefficient (d₃₃) of PYN-xPT single crystals increased with increasing PT content in the rhombohedral phase, being ∼2500 pC/N near the MPB composition (x = 0.46), and decreasing to ∼1200 pC/N for the tetragonal phase crystals. These excellent piezoelectric properties together with the high Curie temperature make PYN-xPT single crystals promising candidates for the applications of high temperature and high performance actuators and transducers.