Anisotropic spin-orbit coupling and magnetocrystalline anisotropy in vicinal Co films

The anisotropy of the spin-orbit interaction, [lambda (a)], in vicinal Co films has been measured using x-ray magnetic linear dichroism (XMLD). A linear increase in [lambda (a)] with Co step density is found using a new sum rule and represents the first experimental confirmation that XMLD probes the magnetocrystalline anisotropy energy (MAE). X-ray magnetic circular dichroism is used to confirm that the XMLD arises from changes in the local step-edge electronic structure. The XMLD sum rule gives a larger MAE compared to macroscopic values and is discussed with respect to other local probes of the MAE.