We present results of density-functional calculations on the magnetic properties of Cr, Mn, Fe and Co nano-clusters (1 to 9 atoms large) supported on Cu(001) and Cu(111). The inter-atomic exchange coupling is found to depend on competing mechanisms, namely ferromagnetic double exchange and antiferromagnetic kinetic exchange. Hybridization-induced broadening of the resonances is shown to be important for the coupling strength. The cluster shape is found to weaken the coupling via a mechanism that comprises the different orientation of the atomic d-orbitals and the strength of nearest-neighbour hopping. Especially in Fe clusters, a correlation of binding energy and exchange coupling is also revealed.
@article{arxiv.0911.3004,
title = {Exchange coupling in transition-metal nano-clusters on Cu(001) and Cu(111) surfaces},
author = {Phivos Mavropoulos and Samir Lounis and Stefan Blügel},
journal= {arXiv preprint arXiv:0911.3004},
year = {2015}
}