Magnetism, structure and chemical order in small CoPd clusters: A first-principles study

• This work analyses the structural and magnetic properties of CoPd nanoclusters.
• The magnetic order is found to be ferromagnetic-like for all the ground-state structures.
• The average magnetic moment per atom increases approximately linearly with Co content.
• The influence of spin–orbit interactions on the cluster properties is discussed.

The structural, electronic and magnetic properties of small ComPdnComPdn(N=m+n=8,m=0−N)(N=m+n=8,m=0−N) nanoalloy clusters are studied in the framework of a generalized-gradient approximation to density-functional theory. The optimized cluster structures have a clear tendency to maximize the number of nearest-neighbor CoCo pairs. The magnetic order is found to be ferromagnetic-like (FM) for all the ground-state structures. Antiferromagnetic-like spin arrangements were found in some low-lying isomers. The average magnetic moment per atom μ¯N increases approximately linearly with Co content. A remarkable enhancement of the local Co moments is observed as a result of Pd doping. This is a consequence of the increase in the number of Co d holes, due to CoPd charge transfer, combined with the reduced local coordination. The influence of spin–orbit interactions on the cluster properties is also discussed.