Circularly polarized soft X-ray and core photoemission in 3d and 4f ferromagnets

The difference in core X-ray photoemission (XPS) between the right and left circularly polarized incident beams, i.e., magnetic circular dichroism (MCD), is discussed for both spin-dominant and orbital-moment-dominant ferromagnets on the basis of an atomic model including multiplet interactions between electrons. As an example of the former, we choose the 2p-core XPS of transition-element systems and give an interpretation to the recent measurement of MCD in 2p XPS for Fe. We next discuss, as an example of the latter, the 3d-core XPS of a rare-earth system with 4f1 configuration, i.e., Ce3+. Core XPS, especially spin-resolved ones, using circularly polarized beams are, furthermore, shown to be a promising method by which to study atomic magnetic states of ferromagnets. (author)