Circular magnetic x-ray dichroism in the heavy rare-earth metals

The calculated circular magnetic x-ray dichroic spectra for the ${\mathit{L}}_3$ absorption edge of the heavy rare-earth metals is presented. For Gd and Tb, the dipolar part is evaluated directly from first-principles relativistic spin-polarized band-structure calculations, while for the others the spectra are obtained by scaling the Gd results. The quadrupolar transitions to the localized 4f states are evaluated separately with full atomic-multiplet calculations, and are found to be large. Implications and experimental results are discussed.