Chemical reaction at ferromagnet/oxide interface and its influence on anomalous Hall effect

Chemical reactions at the ferromagnet/oxide interface in [Pt/Fe]3/MgO and [Pt/Fe]3/SiO2 multilayers before and after annealing were investigated by X-ray photoelectron spectroscopy. The results show that Fe atoms at the Fe/MgO interface were completely oxidized in the as-grown state and significantly deoxidized after vacuum annealing. However, only some of the Fe atoms at the Fe/SiO2 interface were oxidized and rarely deoxidized after annealing. The anomalous Hall effect was modified by this interfacial chemical reaction. The saturation anomalous Hall resistance (Rxy) was greatly increased in the [Pt/Fe]3/MgO multilayers after annealing and was 350% higher than that in the as-deposited film, while Rxy of the [Pt/Fe]3/SiO2 multilayer only increased 10% after annealing.