Growth and electrical properties of 0.88Na0.5Bi0.5TiO3–0.12K0.5Bi0.5TiO3 lead-free piezoelectric single crystal

A large-size 0.88Na 0.5 Bi 0.5 TiO 3 –0.12K 0.5 Bi 0.5 TiO 3 lead-free piezoelectric single crystal with dimensions of ∅30 mm ×10 mm was successfully grown by the top-seeded solution growth method. X-ray powder diffraction measurement showed that the as-grown crystal possesses a rhombohedral perovskite structure at room temperature. The temperature dependence of dielectric constant and loss, polarization hysteresis loop, electric-field-induced strain, and the electromechanical coupling property were investigated for the -oriented as-grown crystal. The remanent polarization P r , the piezoelectric constant d 33 , and the electromechanical coupling coefficient k t at room temperature are 13.8 pC/cm 2 , 205 pC/N, and 51 %, respectively. The maximum strain of 0.23 % was obtained under 30 kV/cm. The temperature dependence of k t demonstrated a relatively stable thermal electromechanical coupling property over the temperature range of 20–150 °C.