Element-specific magnetic properties of Co2(Mn1−xFex)Si films probed by x-ray magnetic circular/linear dichroism

Abstract

Element-specific magnetic properties of epitaxial Co${}_{2}$Fe${}_{x}$Mn${}_{1\ensuremath{-}x}$Si/MgO(100) Heusler films prepared by laser ablation are measured by circular dichroism in x-ray absorption spectroscopy (XMCD). Surface and bulk magnetization of the 100-nm-thick films are equal as tested by comparing the total electron yield and transmission measurements and follow the generalized Slater-Pauling rule. For Co${}_{2}$FeSi, the large magnetization of 6 ${\ensuremath{\mu}}_{B}$ per formula unit indicates half-metallic behavior. Calculations using the local spin density approximation (LDA) result in a half-metallic band structure for this compound when an additional electron-electron-correlation correction ($\text{LDA}+U$) is considered. Simulated XMCD spectra using the LDA and $\text{LDA}+U$ approaches are compared to the experimental spectra. While the electron-electron Coulomb correlation has only a small effect on the observable XMCD spectra, the calculations predict that it will cause a significant change in the x-ray magnetic linear dichroism (XMLD).