The Synthesis of Pure‐Phase Bismuth Ferrite in the Bi–Fe–O System Under Hydrothermal Conditions without a Mineralizer

Abstract

Bismuth ferrite, BiFeO 3 (BFO), was synthesized in a hydrothermal process without the introduction of any metal cations, other than Fe 3+ and Bi 3+ . For this purpose, a strong organic hydroxide was used for the precipitation of the bismuth and iron salts. With the aim to study the molar range for the production of BFO in the Bi–Fe–O system under hydrothermal conditions, the complexity of the phases appearing after the reaction was investigated. Pure‐phase BFO was achieved in the case of a hydrothermal treatment after the coprecipitation of a solution of bismuth and iron salts containing an equimolar ratio of Bi 3+ and Fe 3+ ions. Various iron and bismuth compounds having different morphologies were achieved by changing the Bi 3+ :Fe 3+ ratios in the reaction, but no other bismuth iron oxide phases were observed. To obtain a complete picture of the compounds, we compared the results from transmission electron microscopy with those from X‐ray powder diffraction, energy‐dispersive X‐ray spectroscopy, and scanning electron microscopy. The dielectric properties of the pure BFO and a multiphase system were compared. The pure BFO shows a higher dielectric permittivity than the multiphase system and is comparable with the values reported in the literature.