A first-principles description for the magnetic X-ray dichroism of Pt in Fe

We present a first-principles description for the recently observed magnetic X-ray dichroism of the $L_{2,3}$ X-ray absorption spectra of Pt atoms dissolved in ferromagnetic Fe. We apply the spin-polarized fully relativistic version of the KorringaKohn-Rostoker Green's function method to calculate the electronic structure and use a recently developed relativistic approach to calculate the absorption spectra for left and right circularly polarized X-rays. Our calculations are in good agreement with the exprimental results and provide a detailed, parameter-free explanation for the observed spectra