Possibility of ferroelectric bismuth and nitrogen co-doped barium titanate

The possibility of bismuth (Bi) and nitrogen (N) co-doped barium titanate (BaTiO3) as a ferroelectric material was investigated by calculation and experiment. From first principles calculations, it was found that Bi and N co-doped BaTiO3 has a higher spontaneous polarization than undoped BaTiO3 since dopant Bi and N ions contribute to the enhancement of covalent interactions between cations and anions. Because it was revealed that the ferroelectricity of BaTiO3 can be improved by co-doping of Bi and N, we demonstrated the synthesis of (Ba,Bi)Ti(O,N)(3). Single phase oxynitride (Ba,Bi)Ti(O,N)(3) powder was fabricated by annealing (Ba,Bi)TiO3 in NH3 gas. The tetragonal distortion of (Ba,Bi)Ti(O,N)(3) was smaller than that of BaTiO3, which may be due to A-site and O-site vacancies in the perovskite lattice introduced during NH3 annealing. (C) 2020 The Ceramic Society of Japan. All rights reserved.