Magnetic configurations of rhodium

Two configurations are, a priori, favorable for a possible magnetic ground state of rhodium: small clusters and very thin films. In both cases, the reduction of the average coordination number could allow the onset of magnetism. For clusters, experimental works indicate that Rh, clusters with N similar or equal to 60 have a non-zero average magnetic moment. By using a d-band Hubbard Hamiltonian, the size and the geometric dependence of the magnetic properties of Rh clusters is studied. Different structures and atomic relaxations are considered. Significant magnetic moments are found up to N similar or equal to 50. For thin films of rhodium on silver, the Ag/Rh interdiffusion inhibits a long range magnetic order. The only favorable case is to consider a magnetic substrate. For thin Rh layers on Fe(001) only mono- and bi-layers are polarized. For larger thicknesses, only an interfacial polarization remains. Finally, in agreement with other studies, the Rh semi-infinite crystal does not display a local magnetic moment.