Theoretical description of field-induced magnetic circular x-ray dichroism in nonmagnetic solids

It is demonstrated that the presence of an external magnetic field for a paramagnetic solid gives rise to a circular magnetic dichroism in x-ray dichroism (MCXD) in full analogy to the MCXD observed in ferromagnetic solids. It is shown that the conventional sum rules can be adopted for this situation to give access to the spin and orbital susceptibilities. Results of calculations for various transition metal systems demonstrate the applicability of the sum rules. In particular, for the alloy systems ${\mathrm{Ag}}_x{\mathrm{Pd}}_{1-x}$ and ${\mathrm{Ag}}_x{\mathrm{Pt}}_{1-x}$ use of the field induced MCXD should allow us to study in detail the Stoner enhancement of the spin susceptibility as well as the role of the orbital susceptibility of Pd and Pt, respectively.