Intrinsic orbital and spin magnetism in Rh clusters on inert xenon matrices

Intrinsic orbital and spin magnetic moments of quasifree Rh clusters on inert xenon buffer layers are measured using x-ray magnetic circular dichroism. The moments strongly vary as a function of average cluster size. A maximum total moment of 0.4 B per atom and large orbital-to-spin moment ratios up to 60% appear for RhN clusters with average size N=20, suggesting that cluster geometries are biplanar. The magnetism is further studied between two extreme limits, from quasifree few-atom-sized clusters situated on a xenon layer toward Rh nanostructures in contact with a weakly interacting Ag 100 substrate. Density-functional theory calculations for different cluster sizes and Rh-Ag coordination explain the unexpected quenching of Rh moments in the case of directly deposited Rh on Ag 100 reported by Honolka et al. Phys. Rev. B 76, 144412 2007 .