Structural, electronic and magnetic properties of CoAl (n=1-8) clusters

Based on DFT-GGA calculations, we systematically investigate the structures, electronic and magnetic properties of CoAl (n=1-8) 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 CoAl clusters weakened and the magnetism decreased as compared with that of Co clusters. The reduction magnitude of magnetism of the doping Al accords well with recent Stern-Gerlach experimental result for larger CoAl clusters. In all of the CoAl alloy clusters, the Al atom is found to be aligned antiferromagnetically with its neighbor Co atoms except for CoAl. As compared with the magnetism of pure Co cluster, the magnetism of CoAl cluster is reduced, which is attributed mainly to nor-magnetism Al element embeding and the weakening of spin polarization of the Co atoms. © 2013 Chinese Physical Society.