Dielectric and piezoelectric performance of PMN–PT single crystals with compositions around the MPB: influence of composition, poling field and crystal orientation

This paper presents a detailed study of the dependence of the dielectric and piezoelectric performance on the composition, poling field and crystallographic direction for Pb(Mg1/3Nb2/3)O3PbTiO3 (PMN–PT) single crystal plates with compositions around the rombohedral–tetragonal morphotropic phase boundary (MPB). The Tmax of the plates lies in the range of 130–160 °C. Influence of poling field in a range of 0–3 kV mm−1 on their properties was investigated. Under appropriate poling conditions and with proper compositions, the plates show excellent piezoelectric property with d33 larger than 1800 pC N−1 along 〈001〉 and 〈011〉, and 1300 pC N−1 along 〈111〉, respectively. It is also suggested that the relaxor nature of PMN, the domain structure modulation and the MPB effect all play important roles in influencing the piezoelectric performance. The possibility of the existence of the induced orthorhombic or monoclinic phase is also discussed in this paper.