Magnetic structure of cobalt clusters

The magnetic moments of free standing Co N clusters (4≤ N ≤55) were calculated through a self-consistent spd-tight-binding method. The lowest energy geometrical structures of these clusters were obtained by exhaustive global searches on a many-body Gupta potential energy surface using an evolutive algorithm. The relevant structures mainly follow an icosahedral growth pattern with some fcc-type structures at some particular sizes. The calculated magnetic moments demonstrate a decreasing behavior with cluster size with small superimposed oscillations. The calculations are good agreement with the available experimental data. Our results are briefly discussed and compared with other published theoretical results.