d0 ferromagnetism in undoped n and p-type In2O3 films

Undoped indium oxide films with room temperature d(0) ferromagnetism were prepared by radiofrequency magnetron sputtering with different O-2/Ar flux ratio. The optical and magnetic properties changed non-monotonously as the oxygen flux increases. A conversion of conductivity from n-type to p-type was observed as the flux ratio reached 15:15. The concordant results in structural, electrical, optical, and magnetic properties suggest that single ionized oxygen and indium vacancies play crucial roles in mediating the ferromagnetism in n and p-type In2O3 films, respectively. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4755771]