Unified theory of x-ray magnetic circular dichroism atL2,3absorption edges for a series of Ce compounds

Abstract

A theoretical study is presented with an extended single impurity Anderson model for the spectra of x-ray magnetic circular dichroism (XMCD) at the $\text{Ce}\text{ }{L}_{2,3}$ edges of mixed-valence Ce compounds under an external magnetic field. The effects of magnetic polariztion of the $\text{Ce}\text{ }4f$ states, the exchange interaction between the $\text{Ce}\text{ }4f$ and $5d$ states, and the hybridization between the $\text{Ce}\text{ }4f$ and ligand states are taken into account. Recent experimental results for ${\text{CePd}}_{3}$ are well explained. The theory can be applied to the XMCD of a localized ${\text{Ce}}^{3+}$ system, weakly and strongly mixed-valence Ce systems by changing the hybridization strength, and can also be applied to ferromagnetic Ce compounds by replacing the external magnetic field with the ferromagnetic exchange field. The effects of the hybridization in the final state, the $\text{Ce}\text{ }4{f}^{2}$ configuration, and the spin polarization of the $\text{Ce}\text{ }5d$ states through the hybridization with a spin-polarized ligand band are studied in detail, and a systematic change in the ${L}_{2}$ and ${L}_{3}$ XMCD intensities with the change in the mixed-valence strength is discussed. The present theory gives a framework to understand varied XMCD behavior of a series of Ce compounds in a unified fashion.