MAGNETIC CONFIGURATIONS OF RHODIUM

Two configurations are, a priori, favorable for a possible magnetic gr ound state of rhodium: small clusters and very thin films. In both cas es, the reduction of the average coordination number could allow the o nset of magnetism. For clusters, experimental works indicate that Rh, clusters with N similar or equal to 60 have a non-zero average magneti c moment. By using a d-band Hubbard Hamiltonian, the size and the geom etric dependence of the magnetic properties of Rh clusters is studied. Different structures and atomic relaxations are considered. Significa nt 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 magneti c substrate. For thin Rh layers on Fe(001) only mono- and bi-layers ar e polarized. For larger thicknesses, only an interfacial polarization remains. Finally, in agreement with other studies, the Rh semi-infinit e crystal does not display a local magnetic moment.