Growth and electrical properties of 0.95Na_(0.5)Bi_(0.5)TiO_3-0.05K_(0.5)Bi_(0.5)TiO_3 lead-free piezoelectric crystal by the TSSG method

摘要

0.95Na_(0.5)Bi_(0.5)TiO_3-0.05K_(0.5)Bi_(0.5)TiO_3 lead-free piezoelectric single crystal with rhombohedral structure was grown by the top-seeded solution growth method. The temperature dependence of dielectric constant and loss, polarization hysteresis loops, the optimum poling condition and the electromechanical coupling property were investigated for the < 100>-oriented as-grown crystal. The curves e(T) show two anomalies, which are related to the two phase transformations at the temperature range of 130-340 ℃. The piezoelectric constant d_(33) and electromechanical coupling coefficient k_t for the < 001 >-oriented crystal at room temperature reached 147 pC/N and 0.52, respectively. The value of k_t demonstrated a relatively stable thermal electromechanical coupling property over the temperature range of 15-130 ℃