Growth and characterization of Na 0.5Bi 0.5TiO 3–BaTiO 3 lead-free piezoelectric crystal by the TSSG method

Abstract

In this paper, polycrystalline material of 0.94Na 0.5Bi 0.5TiO 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 °C. A single crystal with dimensions of 25 mm × 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 Å and α = β = γ = 89.2°. At room temperature, the dielectric constant of <0 0 1> 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 <0 0 1>, <1 1 0> and <1 1 1> oriented NBBT98/2 crystal, respectively.