Structure and magnetic properties of nanoparticles of barium ferrite synthesized using microemulsion processing

Abstract

Nanoparticles of barium ferrite (BaFe 12O 19) were synthesized using a novel method called microemulsion processing. In this process, the aqueous cores (typically 5–25 nm in size) of water—cetyltrimethylammonium bromide— n-butanol—octane microemulsions were used as constrained microreactors for the co-precipitation of precursor carbonates (typically 5–15 nm in size). The carbonates thus formed were separated, dried and calcined to form nanoparticles (less than 100 nm) of barium ferrite. The particle size and size distribution were determined by transmission electron microscopy. Phase analysis of the final product by X-ray diffraction confirmed the formation of hexagonal barium ferrite. The powder was further characterized by the measurement of magnetic properties such as coercive field H c, saturation magnetization M s, remanent magnetization M r and loop squareness S r.