Spectral shape of resonant x-ray magnetic diffraction from GdAl2

We have numerically examined the spectral shape of the ratio of the intensity variation upon the magnetization reversal for the 444 reflection of the ferromagnetic intermetallic compound GdAl2 in the vicinity of the Gd L 2 edge and succeeded in roughly reproducing the experimental spectra for two different magnetization directions simultaneously. The main features of the spectral shape are described in terms of the conventional dispersion effects and the resonant magnetic scattering of electric dipole transitions.