Measurement and multiple-scattering calculation of Cu K-edge x-ray magnetic circular dichroism spectra from an exchange-coupled Co/Cu multilayer

Small but significant x-ray magnetic circular dichroic (XMCD) absorptions are observed from an exchange-coupled Co/Cu multilayer at the Cu K edge. Multiple-scattering calculations including the spin-orbit interaction show that the Cu dichroism is almost entirely due to the spin-dependent scattering of photoelectrons by the exchange potentials of Co atoms at the interface. Possible small magnetic moments induced on Cu account for a marginal fraction of the observed Cu dichroism. The calculated XMCD spectra are highly sensitive to the local magnetic structure around the x-ray absorbing site. Layer-resolved magnetic absorption spectra calculated near the K edge of Cu demonstrate that the core excitation on the interface layer dominates the mean XMCD spectrum from the Cu film. Discussion is extended on the effect of interface roughness and the determination of the spin asymmetry of delocalized electrons in Cu layers in the context of the exchange coupling of Co/Cu.