X-MCD Study of Expanded Lattice Permanent Magnet Materials

X-ray magnetic circular dichroism measurements on the cobalt (iron) K edges and samarium L$\text{}_{2}$, L$\text{}_{3}$ edges of Sm$\text{}_{2}$Fe$\text{}_{17}$, Sm$\text{}_{2}$Co$\text{}_{17}$ and their interstitial hydrides and nitrides are reported. Normal absorption profiles show considerable changes upon nitriding for iron- and cobalt K edge and for samarium L$\text{}_{2}$, L$\text{}_{3}$ edges. Much weaker changes are observed upon hydriding. Similarly, significant differences of X-MCD spectra appear between the host Sm$\text{}_{2}$Fe$\text{}_{17}$ (Sm$\text{}_{2}$Co$\text{}_{17}$) and the nitrides, whereas X-MCD signals of the hydrides are similar to those of the hosts. The effects are analysed and discussed in terms of influence of interstitial atom neighbours on the Co(Fe) 4p and Sm 5d electronic bands.