Structural, electronic and magnetic properties of ConAl (n= 18) clusters

Based on DFT-GGA calculations, we systematically investigate the structures, electronic and magnetic properties of ConAl (n= 18) clusters. The results indicate that the aluminum prefers to maximize the number of Co-Al bonds by selecting the site which increases the coordination of cobalt atoms with Al. The doped Al makes the stability of ConAl clusters weakened and the magnetism decreased as compared with that of Con+1 clusters. The reduction magnitude of magnetism of the doping Al accords well with recent Stern-Gerlach experimental result for larger ConAlM clusters. In all of the ConAl alloy clusters, the Al atom is found to be aligned antiferromagnetically with its neighbor Co atoms except for Co4Al. As compared with the magnetism of pure Co cluster, the magnetism of ConAl cluster is reduced, which is attributed mainly to nor-magnetism Al element embeding and the weakening of spin polarization of the Co atoms.