The peculiar magnetism of few-atom binary clusters.
The magnetic properties of small atomic clusters are dominated by quantum size effects and are different from bulk materials. Interesting magnetic phenomena such as the enhancement of spin and orbital moments, large magnetic anisotropies, and size dependent magnetic screening have been predicted, but experimental confirmation is scarce and detailed understanding of the underlying mechanisms is missing. In this research project we will investigate isolated few-atom binary clusters with the objective to build up fundamental knowledge about the magnetic interactions between the atoms and of the interplay of geometric structure and magnetism. Hereto, model clusters will be studied that each address a particular magnetic phenomenon: i) magneto anisotropy energy enhancement in transition metal nanoalloys; ii) tunable exchange coupling in transition metal oxide clusters; and iii) finite size dependent spin-flip screening of local magnetic moments in transition metal and lanthanide doped coinage metal clusters. The geometry of the clusters will be characterized by infrared multiphoton dissociation spectroscopy in combination with ab initio calculations. Total magnetic moments and coupling of spin to the atomic framework will be studied by temperature dependent magnetic deflection experiments. In conjunction with the results of quantum chemical calculations, these experiments will quantify the size and composition dependent exchange coupling in binary clusters.