Iron Oxidation, Interfacial Expansion, and Buckling at theFe/NiO(001)Interface

In order to provide a structural basis for a physical understanding of exchange bias in metal/magnetic-oxide interfaces, we have determined the structure of the $\mathrm{Fe}/\mathrm{NiO}(001)$ interface by means of x-ray absorption spectroscopy and ab initio density functional theory calculations. A Fe-Ni alloyed phase on top of an interfacial FeO planar layer is formed. The FeO layer exhibits a 7% expanded interlayer distance and a 0.3 Å buckling; its presence is predicted to increase the spin magnetic moment of the interface Fe atoms by $0.6{\mu }_B$, compared to the ideally abrupt interface.