Growth of mixed phased films of γ-Fe2O3 and half metallic Fe3O4 using (100) MgO/Fe under layer for spin electronic devices

Half metallic magnetite films using (100) MgO/Fe under layer deposited at room temperature were prepared using facing targets sputtering method. X-ray diffractometry and TEM analyses confirmed epitaxial growth of (100) oriented Fe3O4 layer on (100) oriented MgO under layer prepared on 5nm-thick Fe buffer layer on glass substrates. Resistivity analyses clarified that higher oxygen partial pressure caused higher oxidation of Fe ions in the films which tend to result in γ-Fe2O3. Substrate heating is effective to improve crystallinity and magnetic properties of Fe3O4 film. Oxygen partial pressure of 7.5%, substrate temperature of 150 °C and sputtering discharge current of 0.45A was suitable to prepare magnetite Fe3O4 film with (100) preferential orientation and good magnetic properties.