Microwave-assisted combustion synthesis of CoFe2O4 with urea, and its magnetic characterization

A microwave-assisted combustion method has been utilized to prepare nanophased powders of CoFe2O4 using urea as fuel. The process takes only a few minutes to obtain as-received CoFe2O4. Structural and magnetic properties of the products were investigated by X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy and vibrating sample magnetometry. Magnetization measurements showed that, at the lowest temperature investigated, the coercivity of Co-ferrite is much larger than that of bulk and this is attributed to exchange anisotropy due to spin disorder at the particle surface. (c) 2007 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.