X-ray resonant scattering in the ferromagnet CoPt

Resonant enhancement of the magnetic x-ray scattering has been observed in the ferromagnetic compound CoPt. By measuring the scattered Bragg intensities upon reversal of the magnetization perpendicular to the scattering plane, the asymmetry ratio has been determined for the (220), (331), and the (440) reflections. The resonant line shape of the asymmetry ratios was investigated by tuning the photon energy through the ${\mathrm{L}}_{\mathrm{III}}$ edge of platinum. Values, as large as -0.012, -0.07, and 0.09 for the (220), (331), and (440) reflections, respectively, are observed at the maximum of the resonance. These values are in agreement with the theoretical predictions made for a similar alloy ${\mathrm{Pt}}_3$Mn. The resonant line shape of asymmetry ratios is accounted for by a single 2p⇆5d dipolar electric transition and a magnetic scattering amplitude equal to 0.8 ${\mathit{r}}_0$ per platinum atom.