CALCULATED SP-ELECTRON AND SPD-HYBRIDIZATION EFFECTS ON THE MAGNETIC-PROPERTIES OF SMALL FE(N) CLUSTERS

The ground-state magnetic properties and related electronic properties of small Fe(N) Clusters axe calculated by using an spd-band model Hamiltonian in the unrestricted Hartree-Fock approximation. Results are given for the average magnetic moment per atom mu(N)BAR, the spin-polarized charge distribution within the cluster, and the sp and d electronic density of states. The calculated mu(N)BAR (N less-than-or-equal-to 15) are larger than the bulk value mu(b) = 2.21mu(B). Small local sp magnetic moments are obtained, which in most cases are opposite to the dominant d magnetic moments (mu(sp) congruent-to -0.1mu(B), mu(d) congruent-to 2.5-2.9mu(B)). The role of sp electrons and spd hybridization is discussed particularly, by comparison with previous d-band model calculations. The main quantitative effect obtained by including the sp electrons in the self-consistent calculations is a reduction of about 10% of the value Of mu(N)BAR.