Sonochemical approach to the preparation of barium hexaferrite nanoparticles

A new method, via. the sonochemical decomposition of the solutions of organic precursors, for the synthesis of nanostructured crystalline single phase BaFe₁₂O₁₉ particles is proposed. Nanosized amorphous precursor powders for BaFe₁₂O₁₉, were prepared by the sonochemical decomposition of the solutions of Fe(CO)₅ and Ba[OOCCH(C₂H₅)C₄H₉]₂ in decane, under air at 273 K. The amorphous nature of these particles was confirmed by various techniques, such as SEM, TEM, SAED, and XRD, and the magnetic measurements indicated the superparamagnetic nature. The XRD of the heated sample of this confirmed the formation of single phase BaFe₁₂O₁₉, and the TEM micrograph revealed near uniform platelets with sizes less than 50 nm. The observed magnetization measured upto a field of 1.5 kG of the nanocrystalline BaFe₁₂O₁₉ sample (48 emu g^-1) was significantly lower than that for the reported multidomain bulk particles (72 emu g^-1), reflecting the ultrafine nature of the sample.