Synthesis of nanocrystalline magnetite (Fe₃O₄) films by self-reduction sol-gel route

Nanocrystalline films of magnetite have been prepared by a novel sol-gel route. By use of the self-reduction effect resulted from the reductive gas generated in the heat treatment process of the precursor xerogels films, Fe₃O₄ films with nanoparticles ranging from 20nm to 110nm were successfully prepared under N₂ atmosphere at different temperatures using trivalent iron nitrate as iron source. No organic residues have been detected in the prepared Fe₃O₄ films by the FTIR analysis. The formation mechanism of Fe₃O₄ films was discussed. The coercive force and the saturation magnetization of the resulted films range in 38.9-56.2 Oe and in 58-59 emu/g, respectively. The lower coercive force is advantageous to reducing the required saturated magnetic field in giant magnetic resistance application.