Structural effects on the magnetism of small vanadium clusters

The size and geometric structure dependence of the magnetic properties of small ${\mathit{V}}_{\mathit{N}}$ clusters is studied by using a d-band Hubbard-like Hamiltonian in the unrestricted Hartree-Fock approximation. We determine the average magnetic moment μ${\mathrm{¯}}_{\mathit{N}}$ and local magnetic moments ${\mathrm{\mu }}_{\mathit{i}}$ as a function of the interaction parameters. Different structures are considered and charge transfer effects are discussed. For the considered clusters, usually two different magnetic configurations are obtained. The role of the sp electrons and spd hybridization effects on the magnetic properties is calculated for bcc-like clusters. Results are given for the average magnetic moment, the spin-polarized charge distribution within the clusters, and the sp and d electronic density of states. Small local sp magnetic moments ${\mathrm{\mu }}_{\mathit{s}\mathit{p}}$ are obtained, which in most cases are opposite to the d magnetic moment ${\mathrm{\mu }}_{\mathit{d}}$.