Orientation-tunable ferroelectric and energy storage properties in PMN–PT single crystals

Abstract

The ferroelectric, dielectric and energy storage properties of (1 − x)Pb(Mg_1/3Nb_2/3)O₃–xPbTiO₃ (PMN–PT) can be changed by altering the concentration of PbTiO₃, but a wider scope for performance improvement can be opened by regulating the crystal orientation. Herein, we investigated the orientation dependence of the ferroelectric and energy storage performance of 0.7PMN–0.3PT single crystals with (001), (011), and (111) orientations. An excellent ferroelectric characteristic is obtained in the (111)-oriented PMN–PT single crystals owing to the spontaneous polarization lying along the (111) orientation in the rhombohedral phase. The (001)-oriented PMN–PT exhibits the greatest energy storage efficiency of 64.95% at E = 12 kV cm⁻¹ among the studied crystals, which is attributed to the smallest ratio of remnant polarization to saturation polarization for unipolar polarization–electric field loops. Particularly, a rhombohedral to orthorhombic phase transformation is observed with increasing temperature for the (001)-oriented PMN–PT, affording the largest polarization at high temperature. All the PMN–PT single crystals exhibit excellent antifatigue performance and temperature stability on energy storage.