Structure analysis and systematical electric properties investigation of PSN–PMN–PT single crystal

Abstract

A novel Pb(Sc_1/2Nb_1/2)O₃–Pb(Mg_1/3Nb_2/3)O₃–PbTiO₃ (PSN–PMN–PT) single crystal with large size ϕ25 mm × 40 mm was grown by the Bridgman technique. The crystal was cut along [100] orientation with composition of 6PSN–63PMN–31PT, and then its structure and electric properties were investigated systematically. Raman test demonstrates that the crystal is typical relaxor ferroelectrics with perovskite structure. At room temperature, [100]-oriented 6PSN–63PMN–31PT crystal shows the excellent electric properties, such as the dielectric constant ε_r = 4793, the piezoelectric constant d₃₃ = 1237 pC/N, and the remanent polarization P_r = 34.41 µC/cm², respectively. It is more important that the large coercive field E_c = 8.17 kV/cm in [100]-oriented 6PSN–63PMN–31PT crystal is almost four times than that of PMN–PT, even higher than that of Pb(In_1/2Nb_1/2)O₃–Pb(Mg_1/3Nb_2/3)O₃–PbTiO₃ (PIN–PMN–PT) and Pb(Lu_1/2Nb_1/2)O₃–Pb(Mg_1/3Nb_2/3)O₃–PbTiO₃ (PLN–PMN–PT), indicating its potential application for high-power transducers. With elevating temperature, the [100]-oriented 6PSN–63PMN–31PT crystal shows the large pyroelectric coefficient p = 3.49 × 10⁻² C/m²/K at phase transition temperature, and the related figures of merit (FOMs) for current responsivity F_i, for voltage responsivity Fv and for detectivity F_D increase from 1.968 × 10⁻¹⁰ m/V, 0.00485 m²/C and 0.59 × 10⁻⁵ Pa^−1/2 to 1.396 × 10⁻⁸ m/V, 0.054 m²/C, and 52.94 × 10⁻⁵ Pa^−1/2, respectively. Furthermore, the thermal strain at heating process was analyzed for unpoled and poled crystal.