High magnetic moments in small rhodium-doped neutral cobalt clusters

In the search for new magnetic materials, few atom metal clusters are of great interest because they can posses greatly enhanced magnetic moments with respect to bulk moments per atom. This is particularly the case for bimetallic transition metal clusters. Here, we report on the magnetism of ConRhm (n = 10–45 and m = 0–3) neutral clusters studied in molecular beam experiments using a combination of Stern–Gerlach magnetic deflection and mass spectrometry. Large dopant-induced and size-dependent increases in the total magnetic moment of the clusters were found, of up to 10% per added rhodium atom in the n = 15–30 size range. Density functional theory calculations indicate significant induced local spin magnetic moments on the rhodium atoms but fail to predict systematic enhancement of the spin magnetic moments on the cobalt atoms. The observed large enhancement of magnetic moments suggests an important role of orbital contributions.