Spin-polarized Auger electron spectroscopy on Gd

The spin polarization of all prominent Auger lines of Gd is investigated experimentally. High spin polarization signals are found due to the fully polarized 4f shell. In the low energetic Auger lines initiating from a 4d hole normal and resonant excitations are identified. In particular, the resonant core hole only transition N₄₅{N}₆₇N₆₇ splits in multiplets where the spin polarization gives evidence of spin-flip processes. A reduced polarization of Auger lines involving 3d holes indicates the shortcoming of the LS coupling scheme. We point out that the Gd Auger spin polarization is a key for monitoring this breakdown of spin conservation.