We presented the X-ray magnetic circular dichroism (XMCD) and X-ray absorption spectroscopy (XAS) studies of heavy fermion compound CeAl2 bulk and 8 nm nanoparticles, performed at the Ce M4,5- and L3- absorption edges. XMCD and XAS revealed that Ce in bulk CeAl2 exhibits localized 4f1 character with magnetic ordering. The Ce in nanoparticles, on the other hand, shows a small amount delocalized 4f0 character with non-magnetic Kondo behavior. By applying general sum rules, an estimation of the orbital and spin contribution to those Ce 4f moments can be obtained. Our results also demonstrated that the magnetic behavior in CeAl2 is very sensitive to the degree of localization of the 4f electrons.
Journal of Magnetism and Magnetic Materials 304(1), pp.e22-e24