X-ray magnetic circular dichroism at the rare earth L2,3 edges in R2Fe14B intermetallics

We present a systematic x-ray magnetic circular dichroism (XMCD) study performed at the rare-earth (R) L-2,L-3 edges on the R2Fe14B series. The identification of multipolar contributions to the signal allows the application of sum rules to the obtained XMCD spectra. The results show that both orbital and spinorial components of the R(5d) magnetic moment are proportional to the 4f ones. Hence, the magnetic moment of 5d shell derived from a sum-rules analysis evidences an important nonquenched orbital contribution. This result is in contradiction with Campbell's model for R-Fe intermetallic compounds. Consequently, both XMCD sum rules and Campbell's model have to be revised in the atomic level. (C) 2000 American Institute of Physics. [S0021-8979(00)50408-3].