Magnetic Circular Dichroism in Resonant Raman Scattering in the Perpendicular Geometry at the $\mathit{L}$ edge of $3\mathit{d}$ Transition Metal Systems

We measured circular dichroism in resonant x-ray scattering ${3d}^n\to {2p}^5{3d}^{n+1\mathrm{}}\to {3s}^1{3d}^{n+1\mathrm{}}$ with incidence perpendicular to the magnetization where the absorption dichroism vanishes. The advantages of photon scattering over other techniques make it possible to study a wide range of materials. The Ni $L_3$ dichroism in $\mathrm{NiFe}{}_2\mathrm{O}{}_4$ is $(28\pm 5)\%$ in agreement with a localized model. In the metal Co the dichroism is reduced to $(10.4\pm 1)\%$ $\left(L_3\right)$ and $(6.8\pm 1.5)\%$ ( $7.5\mathrm{eV}$ above $L_3$), indicating a large sensitivity to the nature of the valence states despite the fact that this spectroscopy is based on inner shell transitions.