Sonochemical approach to the preparation of barium hexaferrite nanoparticles

A new method, via. the sonochemical decomposition of the solutions of organ ic 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, s uch as SEM, TEM SAED and XRD, and the magnetic measurements indicated the s uperparamagnetic 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 Mm. The observed magnetization me asured upto a field of 1.5 kG of the nanocrystalline BaFe12O19 sample (48 e mu g(-1)) was significantly lower than that for the reported multidomain bu lk particles (72 emu g(-1)), reflecting the ultrafine nature of the sample. (C) 1999 Acta Metallurgica Inc.