Thermal expansion characteristics of [001]-oriented PIN-PMN-PT single crystal

Thermal expansion characteristics of unpoled and poled 0.23PIN-0.47PMN-0.30PT single crystals were measured in the temperature ranges from -70 to 300°C using DIL402C dilatometer during the heating and cooling process. The thermal expansion anomalies were detected below 0°C, as well as the obvious expansion about 0.11% and contraction about 0.31% along [001] direction was observed respectively around rhombohedral (R) → tetragonal (T) and tetragonal (T) → cubic(C) phase transition temperature for poled PIN-PMN-PT. Compared to the poled single crystal, thermal expansion responded at phase transition temperatures were inconspicuous for unpoled single crystal. The significant differences were exhibited between poled and unpoled crystals, which were related to polarization state and phase transitions in single crystals. The temperature-dependent of dielectric properties were investigated to further confirm the relationships between thermal strain anomalies and phase transition.