Abstract
Films of iron oxides such α-Fe3O3 and Fe3O4 were prepared by evaporating iron in a low pressure atmosphere of oxygen gas and investigated by X-ray and electron diffraction and Mössbauer effect measurements. The formation range of iron oxides was determined as functions of the substrate temperature and the deposition rate at an oxygen pressure of 4×10-4 Torr. The oxide film consisted of fine grains, and the grain size of Fe3O4 increased with increase of the film thickness and the substrate temperature. Magnetic properties were investigated. The coercivity was found to increase up to 1000 Oe with the oxidation of the as-deposited Fe3O4 films. The origin of such high coercivity was briefly discussed.