Local Magnetism of 3d and 4d Impurities in Ag and Pd Clusters

Abstract
The local magnetic properties of Ag₁₂TM and Pd₁₂TM clusters with I symmetry (TM = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Y, Zr, Nb, Mo, Tc, Ru, Rh, and Pd) have been systematically studied with the density functional formalism, and the Kohn-Sham equation is solved self-consistently with the discrete variational method (DVM). A special attention is paid to the comparisons of local magnetism for impurities in Ag and Pd clusters with those in the bulk and on the (001) surface of Ag (Pd), it is found that the behavior of local moments in the Ag₁₂ cluster is more complex than the one of a single impurity in bulk Ag and on the Ag (001) surface, whereas the local moments in Pd₁₂ display very similar features as the ones of a single impurity in bulk Pd and on the Pd (001) surface. In order to better understand these results, the roles of interactions between impurity and host atoms on the local moment of impurities are explored: the interactions of impurity-d with Ag-d orbitals have important contributions to the local magnetic moments for impurities with less than half-filled d shell, such as Sc, Ti, V, Y, Zr and Nb, but have minor roles on the local magnetic moments for impurities Cr, Mn, Fe, Co Ni, Tc, Ru and Rh. However, in the Pd₁₂ cluster, d-d interactions between impurity and host have major roles on all the 3d and 4d impurities. Based on the interaction point of view, explanations are presented for the similarities and differences of moment behavior in the cluster, in the bulk and on the surface. The comparison of the obtained results with those in the Cu₁₂ cluster is also made. This study would provide more comprehensive understandings on the local magnetism of 3d and 4d impurities in different environments.