Hybridization and magnetism in small FePt alloy clusters

Abstract

Magnetic properties of small, mass selected, Fe and FePt alloy clusters deposited on a remanently magnetized Ni/Cu(001) substrate have been investigated using x-ray magnetic circular dichroism. Strong size- and stoichiometry-dependent magnetic properties of Fe and FePt clusters are found, together with enhanced orbital moments compared to bulk and nanoparticles. Compared to pure Fe clusters, FePt alloy clusters have lower orbital and higher spin moments. In addition, they show a higher branching ratio of B _r = L _3 /( L _2 + L _3 ) due to stronger spin–orbital coupling and hybridization.