Synthesis of Magnetic Nanopowders of Iron Oxide: Magnetite and Maghemite

Magnetic iron oxides have been widely used in bio- and agrotechnology, however, procedures of their synthesis can be improved. Magnetic nanopowders whose composition corresponds to magnetite–maghemite solid solutions have been obtained by chemical precipitation from aqueous solutions of iron(II, III) chlorides. Synthesis conditions (exposure to ultrasound, inert gas bubbling, heating to 70°C, keeping in mother liquor) have been shown by scanning and transmission electron microscopy and by computing unit cell parameters for magnetite and maghemite lattice to affect the size, shape, and aggregation extent of nanoparticles. No monophase magnetite and maghemite formed during the synthesis, a solid solution of mixed composition has precipitated.