Electronic structure and magnetic properties of TMRh12 clusters

Abstract

The electronic structure and magnetic properties of Rh 3d transition-metal (TMRh12) clusters are studied by using a linear combination of atomic orbitals and molecular orbitals method within the density functional theory. The equilibrium bond lengths obtained for TMRh12 clusters compare well with other theoretical results and show a small contraction in comparison with those of Rh13 and bulk interatomic spacings. A contraction trend is also established for TMRh12 with an increase in the atomic number of the TM atoms. A mechanism leading to a giant magnetic moment on Rh and a local magnetic moment on impurities is discussed in detail. An interesting antiferromagnetic-to-ferromagnetic switch of impurities with an increase in the atomic number is found and accounted for in terms of the virtual bound-state model. The relationship between magnetic moments of the clusters and the interatomic spacing is investigated systemmatically, and superparamagnetic behaviour for some TMRh12 clusters is found. © Springer-Verlag 1996.