Surface magnetic x-ray diffraction experiments have been done on the (111) surface of the ferromagnetic alloy Co3Pt. This has been achieved by tuning the photon energy to the LIII absorption edge of Pt in order to benefit from the increased magnetic cross section at resonance Analysis of the data reveals that the magnetism of the Pt atoms on the first atomic layer is smaller by about a factor of 2 than that of the Pt atoms in the bulk the reason probably being the reduced Co concentration at the surface.

Phys. Rev. Lett.

Ferrer, S, Fajardo, F, de Bergevin, F, Alvarez, J, Torrelles, X, van der Vegt, H. A, & Etgens, V. H. (1996). Resonant surface magnetic x-ray diffraction from Co3Pt(111). Phys.Rev.Lett., 77, 747–750.