Lead-free piezoelectric single crystal of [Bi-0.5(Na1-xKx)(0.5)]TiO3(BNTKx) with size of 10 x 10 x 5 mm(3) has been successfully grown by the self-flux method. The temperature dependence of dielectric constant was measured and the peak temperature of dielectric constant was found to be 45 degrees higher than that of pure (Bi0.5Na0.5)TiO3 crystal. X-ray diffraction pattern indicated that the BNTK50 crystal is tetragonal (symmetry group 4 mm) with a = b = 0.3917 nm and c = 0.4011 nm, respectively. Differential scanning calorimetry showed that the crystal was congruent melting during growth. Superior piezoelectric and electromechanical properties were found in these lead-free crystals. (c) 2005 Elsevier B.V. All rights reserved.