Electric field dependent phase stability and structurally bridging orthorhombic phase in crystals near the MPB

The dielectric, domain and structural properties of Na0.5Bi0.5TiO3-5.2%BaTiO3 (NBT-5.2%BT) single crystals were studied as a function of temperature in unpoled and 〈 001 〉 -poled conditions. A rhombohedral phase was found to coexist with a small volume fraction of a tetragonal one in the unpoled condition. However, in the poled condition, a single c -domain tetragonal state was found to be stable at room temperature with a piezoelectric d 33 constant of 400 pC/N. On heating above 105 °C, this single c -domain tetragonal state first transformed into an intermediate orthorhombic structure at 130 °C, and then subsequently into a rhombohedral one above 140 °C.