Magnetism due to oxygen vacancies and/or defects in undoped semiconducting and insulating oxide thin films

Room temperature ferromagnetism was observed in HfO 2, TiO 2, and In 2O 3 films grown on yttrium-stabilized zirconia, LaAlO 3, and MgO substrates, respectively. While the magnetic moment is rather modest in the case of In 2O 3 films, it is very large in the other two cases. Thin film form, which might create necessary defects and/or oxygen vacancies, must be the main reason for undoped semiconducting and insulating oxides to become ferromagnetic. From the results, a serious question arises if a transition-metal doping indeed plays any essential role in producing ferromagnetism (FM) in non-magnetic oxides.