Circular Dichroism in the 3dand 4dCore Photoabsorption for Ferromagnetic Ce Compounds -Interplay of Hybridization, Spin Orbit Interaction and Crystal Field-

The Ce 3 d - and 4 d -core photoabsorption spectra (3 d XAS and 4 d XAS) of ferromagnetic mixed valent Ce compounds are calculated on the basis of the impurity Anderson model. The model takes into account the Coulomb interaction producing multiplet structures, the spin-orbit interaction, the crystal field effect and the molecular field acting on the 4 f spin. The calculation shows a strong circular dichroism even for the Ce magnetic moment of ∼0.5 µ B . The dichroism is furthermore shown to be a powerful method to measure the spin and orbital contributions to the 4 f moment. On the basis of the calculation, the 4 f magnetic state of the ferromagnet CeRh 3 B 2 is discussed.