Magnetic behavior and role of the antiphase boundaries in Fe_3O_4 epitaxial films sputtered on MgO (001)

摘要

Magnetite Fe_3O_4 films were grown on single crystal MgO (001) substrates using facing target sputtering technique. Conversion Electron Mossbauer Spectroscopy and magneto optical polar Kerr spectra have confirmed the stoichiometric repartition of Fe cations corresponding to the inverse spinel structure and the electronic structure characteristic of bulk Fe_3O_4. Hysteresis loops carried out at room temperature show that, in a 1 T applied magnetic field, only 60% of the saturation magnetization is detected. This behavior is discussed in correlation to the antiphase boundaries (APBs) observed by electron microscopy. Magnetic force microscopy studies show that magnetic domains are larger than the mean distance between APBs.