Preparation and characterization of amorphous nanometre sized Fe₃O₄powder

Abstract

A method for the preparation of amorphous Fe₃O₄ powder with a particle size of ca. 25 nm is reported. Amorphous Fe₃O₄ powder can be simply synthesized by slowly exposing amorphous Fe powder to the air. The amorphous properties of Fe₃O₄ nanoparticles were characterized by X-ray diffraction, Mössbauer spectroscopy, transmission electron micrography, differential scanning calorimetry and quantum design SQUID magnetization measurements. This amorphous Fe₃O₄ powder is superparamagnetic and its magnetization at room temperature is very low (<1.5 emu g^-1); it crystallizes at 285±15 °C.

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