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) TiO3 lead-free piezoelectric single crystal with dimensions of 30 mm x10 mm was successfully grown by the topseeded 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 < 100 >-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 degrees C.