Structure, frequency dependent dielectric properties and domain configuration of PMN–PFN–PT single crystal

• PMN–PFN–PT single crystal was grown successfully from high temperature solution by slow cooling method.
• The as-grown PMN–PFN–PT single crystal was in an intermediate state between normal and relaxor ferroelectrics.
• Dielectric permittivity and loss of [0 0 1]-oriented PMN–PFN–PT single crystal exhibited different frequency dependence with that of PMN–PT65/35 single crystal.
• Domain configuration of poled [0 0 1]-oriented PMN–PFN–PT was observed for the first time using a polarized light microscopy (PLM).

Pb(Mg1/3Nb2/3)O3–Pb(Fe1/2Nb1/2)O3–PbTiO3 (PMN–PFN–PT) single crystal was grown successfully from high temperature solution by slow cooling method. Structure, frequency dependent dielectric properties and domain configuration of [0 0 1]-oriented single crystal have been investigated. X-ray diffraction analysis showed that the as-grown single crystal had a pure perovskite structure with tetragonal symmetry at room temperature. The temperature dependent dielectric permittivity showed only one dielectric anomaly, indicating the ferroelectric–paraelectric phase transition. According to the modified Curie–Weiss relationship, as-grown PMN–PFN–PT single crystal was in an intermediate state between normal and relaxor ferroelectrics. Dielectric permittivity and loss of [0 0 1]-oriented PMN–PFN–PT single crystal at room temperature decreased sharply with increasing frequency, which were different from those of PMN–PT65/35 single crystal. Domain configuration of [0 0 1]-oriented PMN–PFN–PT single crystal was observed for the first time by using a polarized light microscopy (PLM). The extinction of 90° domains at P/A:0° revealed a tetragonal structure. Domains along (0 0 1) face exhibited a straight stripe-like morphology with domain size on the scale of 10 μm in average, combining with some much smaller domains about 3–5 μm in width at the intersection of domain blocks which helps to minimize its total energy.