Growth and characterization of relaxor ferroelectric Pb(Fe _2/3W_1/3)O₃PbTiO₃ single crystals

Single crystals of the complex perovskite solid solution (1-x)Pb(Fe _2/3W_1/3)O_3-xPbTiO₃ [(1-x)PFWxPT], with x = 0, 0.07, 0.13, 0.27 and 0.75, have been synthesized by the high temperature solution growth using PbO as flux, and characterized by X-ray diffraction and dielectric measurements. With the increasing amount of PT, the crystal structure at room temperature changes from a pseudo-cubic (x = 0, 0.07 and 0.13) to a tetragonal phase (x≥0.27). The dielectric properties of the crystals exhibit a typical relaxor behaviour for x = 0 to 0.27 with frequency-dependent peak temperature (T_m) satisfying the Vogel-Fulcher law, while the crystals with higher PT-content undergo a first-order transition at the ferroelectric Curie temperature T_C.