Compositional dependence of properties of Pb(Yb1/2Nb1/2)O3–Pb(Mg1/3Nb2/3)O3–PbTiO3 ternary ferroelectric crystals

Abstract

A series of Pb(Yb_1/2Nb_1/2)O₃–Pb(Mg_1/3Nb_2/3)O₃–PbTiO₃ ternary ferroelectric crystals with different compositions have been grown by the top-seeded solution growth technique in order to investigate systemically this ternary system based on the single crystal form. The compositional segregation and the compositional dependence of electric properties have been studied for the selected compositions in the vicinity of the morphotropic phase boundary (MPB) region. All the samples exhibit perovskite structure with rhombohedral symmetry at room temperature. The lattice parameter (a), coercive field E_c, Curie temperature T_C, the rhombohedral–tetragonal phase transition temperature T_rh–te increase gradually with increasing PYN content. All the samples exhibit quite high piezoelectric performance. In particular, the crystal with composition 0.20PYN–0.40PMN–0.40PT possesses excellent electric properties such as T_C = 180 °C, T_rh–te = 130 °C, k₃₃ = 90.9%, d₃₃ = 2240–2580 pC N⁻¹, P_r = 28.4 μC cm⁻² and E_c = 5.4 kV cm⁻¹, indicating that the PYN–PMN–PT ternary crystals will be a promising candidate for electromechanical applications.