Characterization study of the growth and electromechanical properties of 67PMN-33PT single crystals

A modified Bridgman approach, developed at the Shanghai Institute of Ceramics, Chinese Academy of Sciences (SICCAS), has been used to grow ferroelectric relaxor PMN-PT single crystals. A series of technological barriers on the growth of ferroelectric relaxor PMN-PT single crystals, such as making seeds, seeded-orientation control, size-enlargement, uniformity of the grown single crystals, and crucible leakage, have been progressively overcome. After poling, the electromechanical properties of the grown PMN-PT single crystals are; weak-field permittivity max (ε_max) ∼ 29,000 at 162°C, 1 kHz and 1 V_rms, dielectric loss (tan δ) < 0.9%; piezoelectric coefficient d₃₃ > 2,000 pC/N; mechanical-electric coupling factors, k₃₃ ∼ 0.92-0.94 and k_t ∼ 0.61-0.62, respectively. The electromechanical properties of the 67PMN-33PT single crystal composition are measured as a function of temperature. This analysis reveals the effects of the diffuse phase transition on the electromechanical properties as piezoelectricity in the material develops.