Mössbauer study of Fe-oxide surface layers formed on small Fe particles

A Mössbauer study has been made of the iron-oxide formed on the surface of ultrafine Fe particles (about 293 Å in diameter) prepared by an aerosol method. Particular attention has been paid to the morphology of the oxide layers and to the magnetic structure. X-ray analyses indicate that the oxide layer is a mixture of Fe₃O₄ and γ-Fe₂O₃, and is composed of divided fine crystallites. Further a large non-collinearity in the spin structure of the oxide layer is found that is the likely origin of the low saturation magnetization observed for this type of system.