Cluster Model Calculation for X-Ray Magnetic Circular Dichroism at Rare-Earth (R) L _2,3 Absorption Edges in R ₂Fe ₁₄B

X-ray magnetic circular dichroism (MCD) at the L _2.3 absorption edges for the entire series of rare-earth (RE) elements in R ₂Fe ₁₄B (R = RE) is studied based on a cluster model including 10 RE and 16 Fe atoms. The cluster model takes into account band effects of RE 5d states, to which the electric dipole transition occurs from the core 2p states, as well as spin polarization of the 5d states due to the interatomic hybridization with the spin polarized Fe 3d states. We also take into account spin and orbital polarization of the 5d states due to the 5d-4f intra-atomic exchange interaction, and the 2p to 4f quadrupole transition. The calculated results are in satisfactory agreement with experimental ones, suggesting that the cluster model calculation provides a new method to calculate quantitatively MCD spectra of RE systems with complicated atomic arrangements.