Influence of preparation method on phase formation, structural and magnetic properties of BiFeO3

Abstract

Nanocrystalline BiFeO₃ was synthesized utilizing two distinct techniques: auto-combustion and ceramic. A unique auto-combustion process employing glycine as a fuel has been used to synthesize single-phase BiFeO₃ nanoparticles. Well mixed metal nitrates combust, producing BiFeO₃ nanoparticles, which crystallize in a rhombohedral perovskite structure. The average particle size of 16 nm was estimated using Rietveld refinement of the X-ray diffraction data. The X-ray diffraction data for the solid-state prepared sample shows the formation of BiFeO₃ with the same rhombohedral perovskite structure with an average particle size of 101 nm with additional secondary phases corresponding to Bi₂Fe₄O₉/Bi₂O₃ and Bi₂₅FeO₃₉. By increasing the sintering time Bi₂Fe₄O₉/Bi₂O₃ phase disappeared after 3 h of heating and reappeared again after 5 h of sintering. The changing of sintering time was not able to reduce the Bi₂₅FeO₃₉ formation. The TEM estimated average particle size confirms the XRD analysis. M(H) hysteresis loop shows a G-type magnetic structure. Due to the small particle size, the periodicity of canted spins was broken, and the magnetization of the auto-combustion prepared sample is approximately eight times greater than the ceramic prepared one. The importance of pure phase BiFeO₃ came from its potential applications in sensors, data storage, spintronics devices, and reports of greatly enhanced ferroelectricity in epitaxially strained thin films.