EFFECT OF FUEL ON THE AUTO-COMBUSTION SYNTHESIZED MULTIFERROIC BiFeO3

Abstract

Bismuth ferrite is one of the most promising single multiferroic materials. It exhibits ferroelectric and antiferromagnetic behavior in wide range of temperatures. Many new applications arise due to possibility of magnetization reorientation by electric field and polarization reorientation by magnetic field [1]. Main problem in usage of BiFeO3is difficulty of obtaining pure phase ceramic and high conductivity as a result of Fe non-stoichiometry [2]. BiFeO3 powders were prepared by auto-combustion method starting from iron and bismuth nitrates. After the process of self-ignition, fine precursor powders were thermally treated for various periods at different temperatures and heating rates. Several fuel to oxidizer ratios (F/O) were examined, and X-rays diffraction results showed that in case of citric acid as a fuel, the purest BiFeO3 perovskite phase was obtained for F/O = 1/1 and calcination at 600 °C by 4 hours. However, some Bi2O3, Bi2Fe4O9 and Bi25FeO39 secondary phases remains in all powders. Effect of other fuels (sucrose, urea) [2,3] and sintering regimes are still to be investigated. Powders were characterized by SEM/EDS, TG/DTA, Raman scattering, particle size distribution and BET surface area measurements. Impedance measurements of BiFeO3 ceramics are planned.