Structural and electric properties of (Na_0.5Bi_0.5)_0.88Ba_0.12TiO₃

Lead-free (Na_0.5Bi_0.5)_0.88Ba_0.12TiO₃ ceramics have been prepared and studied by X-ray diffraction and by the complex dielectric response as a function of temperature, frequency and a.c. field intensity. Relaxor-like dielectric behaviour were induced by barium Ba dopping to Na_0.5Bi_0.5TiO₃. It was shown, that relaxor-like characteristics can be enhanced by the increase of the a.c. field intensity. A sharp increase in the electric permittivity and dielectric loss on heating near 230 °C has been observed. This sharp increase in dielectric responses indicates a transformation between classical and relaxor ferroelectric phases. The X-ray diffraction study shows that this transformation corresponds to the first order phase transition from tetragonal to cubic. The use of (Na_0.5Bi_0.5)_0.88Ba_0.12TiO₃ ceramics for device applications has been indicated.