Giant magnetic moments in 4d clusters

Electronic structure of 13-atom clusters of 4d nonmagnetic solids Pd, Rh, and Ru has been studied using a linear combination of atomic orbitals molecular-orbital approach within the density functional formalism. Pd₁₃, Rh₁₃, and Ru₁₃ are all found to have nonzero magnetic moments. Unexpectedly, the ground state of Rh₁₃ is found to have 21 unpaired electrons and thus a magnetic moment of 21μ_B. These 4d-element magnetic moments are a result of the reduced dimensionality and the enhanced electronic degeneracy due to the symmetry of the cluster. The effect of impurities on the moments is examined through calculations on FePd₁₂, FeRh₁₂, RhPd₁₂, and RuPd₁₂ clusters.