Interfacial magnetic structure in Fe/NiO(001)

I. INTRODUCTION Nanocomposite magnetic systems composed of different phases, each exhibiting a specific magnetic behavior and coupled by their mutual interaction, can be designed to obtain artificial materials with novel and potentially useful magnetic properties. Among these systems of particular interest are coupled ferromagnetic (FM)/antiferromagnetic (AFM) materials, which present a unidirectional anisotropy, known as exchange bias. 1,2 An insightful understanding and control of the magnetic properties of nanocomposite systems requires a description of the materials at the atomic scale. A general quantitative explanation of the exchange bias is still not available, in spite of the great effort by many researchers and the numerous studies performed; there is a consensus that this is mostly due to a poor understanding of the interface between the two materials in terms of its local atomic structure and magnetic couplings. In general, the magnetic structure of FM/AFM interfaces has to be taken into consideration in the models to correctly predict the overall magnetic behavior of the investigated system. To simplify at least part of the complexity of these systems, well-controlled epitaxial FM/AFM bilayers can be used in experimental studies. Oxides have been very often used as