Temperature and DC bias dependence of the phase transition behavior of [011]- and [001]-oriented PIN-PMN-PT single crystals with MPB composition

The phase transition behavior of [011]- and [001]-oriented 0.24PIN-0.43PMN-0.33PT single crystals was investigated through dielectric measurement in the process of heating and direct current (DC) bias. The phase transformation sequence in the [011]-oriented crystals is rhombohedral (R) → monoclinic (M_B) → orthorhombic (O) → monoclinic (M_C) → tetragonal (T) → cubic (C). The phase transition temperatures of R to M_B (T_R-MB) and M_B to O (T_MB-O) decrease; meanwhile, the transition temperatures of O to M_C (T_O-MC) phase, M_C to T (T_MC-T) phase, and T to C (T_T-C) phase increase with the increase of DC bias. The phase transformation sequence in the [001]-oriented crystals is R → T → C. As DC bias increases, the transition temperature TR-T of R to T phase declines and the transition temperature TT-C rises. Intermediate phases MB, O, and MC are only found in the [011]-oriented crystal. The phase transition characteristics of the [011]-oriented crystals are rather more complex than those along [001] direction. The micro-macro domain transition at Tf is related to crystal orientation and DC bias voltage. The phase diagram in terms of temperature and bias voltage is established for [011]- and [001]-oriented 0.24PIN-0.43PMN-0.33PT crystals. The DC bias dependent dielectric properties and phase transition characteristics are also compared with the crystals along [111] direction.