Effects of site occupancy and valence state of Fe ions on ferromagnetism in Fe-doped In2O3 diluted magnetic semiconductor

The effects of oxygen vacancies, valence state of Fe ions, and site occupancy of Fe ions on ferromagnetism in Fe-doped In2O3 were investigated both experimentally and theoretically. The Fe3+ ions prefer to occupy the 8b sites and do not contribute to the room temperature (RT) ferromagnetism. It is found that the presence of Fe2+ ions in In2O3 can be induced through the creation of oxygen vacancies. The Fe2+ ions tend to occupy the 24d sites, and the origin of RT ferromagnetism can be related to the strong Fe:4s and Fe:3d hybridization. Our findings not only give a clear picture on the origin of ferromagnetism of Fe-doped In2O3 but also provide a way to tune the magnetic property of Fe-doped In2O3 through the control of valence states of dopant and the control of sites for dopant occupation.