The magnetic moment reduction of fullerene encapsulated gadolinium. A combined effect of spin-orbit interaction and anisotropic hybridisation

We propose a theoretical model to account for the recently observed magnetic moment reduction of gadolinium in fullerenes. While this reduction has been observed also for other trivalent rare-earth atoms (Dy<Superscript>3+</Superscript>, Er<Superscript>3+</Superscript>, Ho<Superscript>3+</Superscript>) in fullerenes, and can be ascribed to crystal field effects, the explanation of this phenomena for Gd<Superscript>3+</Superscript> is not straightforward due to the spherical nature of its ground state (S=7/2, L=0). In our model the momentum reduction is the result of a subtle interplay between hybridisation and the spin-orbit interaction. Copyright EDP Sciences/Società Italiana di Fisica/Springer-Verlag 2005