X-ray magnetic circular dichroism temperature dependent study of RCo2 compounds

We have performed a temperature-dependent study of the rare earth L2,3 and Co K edges x-ray magnetic circular dichroism (XMCD) in HoCo2 and PrCo2. We have found in both samples that the L2/L3 ratio is temperature independent. This result contradicts previous findings that indicated a possible different behavior for L2 and L3 edges owing to modifications in the degree of 3d–5d hybridization. A further interesting result is that the temperature dependence of ratio E1/E2 for the L3 edge — where E1 and E2 correspond to the two area under the dichroic signal separated in two peaks, positive dipolar dominant, negative with significant contributions of both dipolar and quadrupolar channels — is also constant, suggesting that the dipolar and quadrupolar channels follow the same temperature dependence. This effect might be interpreted as the dominant 4f contribution to the 5d polarization (much larger than the 3d-induced contribution) to create the L-edge XMCD signal. The microscopic origin of the metamagnetic Co subsystem is also addressed.