X-ray absorption spectroscopy for crystallographic and magnetic characterizations of metallic superlattices

The site selectivity of XAS is a key element in determining local crystallographic order. The bidimensionality of multilayers creates new phases with stacking anisotropy probed thanks to the linearly polarized photons. The bcc cobalt in Fe-Co, bcc copper in Cu-Fe,..., bcc-derived hexagonal iron stacking in Fe-Ru are all XAS findings. The magneto-optics includes circularly polarized X-ray photons applied to ferromagnetic systems. The site and symmetry selectivities are once again valuable to determine the nature (magnitude) of the magnetic coupling between elements in Co-Cu and Co-Fe, and to distinguish between magnetic interface and chemical interface as evidenced in Nd-Fe multilayers.