Magnetic properties of clusters of transition metal atoms

Using a newly proposed calculational scheme that combines the Hubbard approximation with the tight-binding molecular-dynamics method, we obtain the magnetic moments of Fe-n and Ni-n clusters with cluster size up to n = 55 in a systematic way. Our results indicate that the average magnetic moment per atom is significantly higher in the cluster than in the bulk, in agreement with recent experimental data for Fe and Ni clusters. Furthermore, it is found that magnetic effects stabilize the clusters in geometries that were found to be completely unstable when magnetism is ignored. In general, magnetic effects drive Fe (and to a lesser extent Ni) clusters into geometries of higher symmetry than that of the corresponding singlet states.