XPS analyses of Ta/MgOx/Ni81Fe19/MgOx/Ta films

Ta/MgOx/Ni81Fe19/MgOx/Ta films were prepared by magnetron sputtering. The anisotropic magnetoresistance (AMR) increases dramatically after annealing. The chemical states of Ta and MgOx at the interface of the NiFe/MgOx/Ta films, which were prepared at the different technological conditions, were analyzed by X-ray photoelectron spectroscopy (XPS). The results show that the AMR of the films is related to the chemical states of MgOx. The chemical states of Mg are different when MgOx is prepared at different technological conditions. Therefore, increasing the AMR is beneficial when more Mg2+ ions are present in the MgOx films.