Ferromagnetism in N-doped In_2O_3 films prepared by thermal oxidation

摘要

Two series of N-doped In_2O_3 films were prepared by annealing the sputtered InN films in air at different temperatures and for different time. The corresponding structural and magnetic properties are studied. An apparent transformation from the wurtzite InN to the cubic bixbyite In_2O_3 is observed with increasing the annealing temperature. Room temperature d~0 ferromagnetism is detected, which is found to be closely related with the annealing conditions. We think that the ferromagnetism is derived from the N-doping which substitute the positions of the oxygen atoms in the In_2O_3 lattice, and an indirect ferromagnetic coupling can be established between the doped N atoms via the hybridized O 2p and In 5p/4d orbitals.