Effect of interface NiO layer on magnetism in Fe/BaTiO3 thin film

The insertion effect of an interface NiO layer on magnetism in Fe/BaTiO3 is investigated by X-ray absorption spectroscopy (XAS). From X-ray magnetic circular dichroism (XMCD) analysis, the enhancement of remanent magnetization in Fe is observed with increasing NiO thickness. We also find that the NiO layer is partially composed of metallic Ni, and its thickness is estimated to be similar to 0.4 nm from the NiO-thickness dependence of the Ni XAS intensity by assuming that Ni is localized at the interface between Fe and NiO. Moreover, extended X-ray absorption fine structure data shows that the Ni-O distance of the interface NiO layer is shorter than that of bulk NiO, which leads to the pseudomorphic growth of NiO on BaTiO3. We thus suppose that the improved Fe growth promoted by the interface NiO layer enhances the magnetic moment in Fe. (C) 2018 The Japan Society of Applied Physics