Magnetic characteristics of Er(Mn_12-xFe_x) compounds (x = 7, 9) determined by X-ray magnetic circular dichroism

The RMn_12-xFe_x series of compounds of ThMn₁₂ structure type exhibit particularly complicated and composition sensitive magnetic properties. Previous neutron diffraction and magnetisation experiments have permitted to relate the main features to the strength of the local magnetic moments (3d polarisation) and the nature exchange forces between the Mn, Fe and R sublattices. X-ray magnetic circular dichroism analyses have been undertaken on iron rich compounds with R = Er. They allow to better understand the thermal and field behaviour of the local magnetic moments as well as the nature of the magnetic couplings between the 3d metals.