First principles study of small cobalt clusters encapsulated in C60 and C82 spherical nanocages

Structural, electronic and magnetic properties of the small Co_n clusters (n = 2-7) endohedrally doped in C₆₀ (Ih) and C₈₂ (C2v) fullerenes were investigated using ab initio calculations based on the density functional theory. It is found that the encapsulated Co_n clusters inside C₆₀ and C₈₂ cages are energetically favorable except for Co₇@C₆₀. The encapsulation does not change significantly the structure of the enclosed clusters, but the magnetic moment of the clusters reduces due to a stronger Co-C hybridization for the larger clusters.