Effect of vacuum-annealing on the d0 ferromagnetism of undoped In2O3 films

► Effect of vacuum-annealing on the d0 ferromagnetism of pure In2O3 films. ► d0 ferromagnetism both exists in the as-grown and vacuum-annealed In2O3 films. ► Highly oxygen-deficiency state of the annealed In2O3 film was characterized by XPS. ► An enhancement in the moment from 0.5 to 5.5 emu/cm3 was achieved upon annealing. ► The d0 ferromagnetism in our pure In2O3 films is related to oxygen vacancies.