A study of ferroelectric properties of Bi₄Ti₃O₁₂ ceramics prepared from chemically derived powders

Abstract

The coprecipitation method was used for the preparation of chemical powders as the starting material in the processing of bismuth titanate ceramics. The proposed procedure is based on the hydrolysis of titanium (III) or titanium (IV) chloride in an aqueous solution of bismuth nitrate. Bismuth titanate ceramic was obtained by reaction sintering of annealed powders. The formation of Bi₄Ti₃O₁₂ in the sintered samples was confirmed by X-ray diffraction analysis. When the titanium was introduced as TiCl₃ an essentially single phase product with ratio Bi₂O₃/TiO₂=2:3 was obtained. In the ceramic derived from TiCl₄ as starting reagent, an additional phase containing Bi₂Ti₄O₁₁ (Bi₂O₃/TiO₂=1:4) was found. The values of dielectric permittivity derived from the capacity measurements, ϵ _A =114, ϵ _B =107, were in good agreement with values calculated by means of the Shulgasser model: ϵ _Acalc=116.4, ϵ _B,calc=103.4. The hysteresis loops and derived values of coercive field, spontaneous and remanent polarization, indicates the ferroelectric behavior of the obtained ceramic material.