Growth of Pb(Fe _1/2Nb _1/2)O ₃-Pb(Yb _1/2Nb _1/2)O ₃-PbTiO ₃ piezo-/ferroelectric crystals for high power and high temperature applications

In order to develop new piezoelectric crystals with high T _C and high performance for high-power and high-temperature applications, the Pb(Fe _1/2Nb _1/2)O ₃-Pb(Yb _1/2Nb _1/2)O ₃-PbTiO ₃ [PFN-PYN-PT(10/38/52)] ternary piezo-/ferroelectric single crystals have been grown by the flux method for the first time. The crystal structure has been characterized by means of X-ray diffraction technique, showing a perovskite phase with rhombohedral symmetry at room temperature. The as-grown PFN-PYN-PT crystal possesses a high Curie temperature (T _C) of 325 °C and a high rhombohedral-tetragonal phase transition temperature (T _rt) of 155 °C. Complete electric characterization has revealed the high performance of the ternary crystals, with a dielectric constant ε′ = 1620, a piezoelectric coefficient d ₃₃ = 1100 pC N ^-1, a longitudinal electromechanical coupling factor k ₃₃ = 70%, a remnant polarization P _r = 25.8 μC cm ^-2, a coercive field E _c = 10.3 kV cm ^-1, and a mechanical quality factor Q _m = 110 for (001)-oriented crystals at room temperature. These results show that the PFN-PYN-PT crystals are a promising candidate for uses in electromechanical transducers for high-power and high-temperature applications.