Growth and characterization of Na0.5Bi0.5TiO3-BaTiO3 lead-free piezoelectric crystal by the TSSG method

In this paper, polycrystalline material of 0.94Na(0.5)Bi(0.5)TiO(3)-0.06BaTiO(3) (abbreviated as NBBT94/6) was synthesized by solid-state reaction techniques. DTA and TG analysis indicate the proper temperature for solid-state reaction is 1200 degrees C. A single crystal with dimensions of 25 turn x 10 mm was successfully grown by using the top-seeded solution growth (TSSG) method. X-ray fluorescence analysis revealed that the composition of the as-grown crystal is NBBT98/2. X-ray powder diffraction results show that the as-grown NBBT98/2 crystal possesses the perovskite structure and belongs to the rhombohedral system. The unit-cell constants of the as-grown NBBT98/2 crystal are a = b = c = 3.8862 angstrom and alpha = beta = gamma = 89.2 degrees. At room temperature, the dielectric constant of (001) oriented NBBT98/2 crystal is 770 at 10 kHz and it decreases to 430 after poling under the E-field of 7 kV/mm. Maximum d(33) values of 60, 65 and 30 pC/N were obtained for (001), (110) and (111) oriented NBBT98/2 crystal, respectively. (C) 2007 Elsevier B.V. All rights reserved.