Giant magnetic moments in 4 d clusters

Abstract

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. ${\mathrm{Pd}}_{13}$, ${\mathrm{Rh}}_{13}$, and ${\mathrm{Ru}}_{13}$ are all found to have nonzero magnetic moments. Unexpectedly, the ground state of ${\mathrm{Rh}}_{13}$ is found to have 21 unpaired electrons and thus a magnetic moment of 21${\mathrm{\ensuremath{\mu}}}_{\mathit{B}}$. 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 ${\mathrm{FePd}}_{12}$, ${\mathrm{FeRh}}_{12}$, ${\mathrm{RhPd}}_{12}$, and ${\mathrm{RuPd}}_{12}$ clusters.