Magnetism of small Mn clusters

The role of structure on the magnetic properties of Mn clusters is investigated by performing calculations for different growth families, icosahedral, bcc and fee. The spin-polarized electronic properties of these geometries are calculated by solving an spd tight-binding Hubbard-like Hamiltonian in the unrestricted Hartree-Fock approximation by using a bulk-like parametrization, extra orbitals of s-like character being added to take into account spillover effects present in transition metal clusters. Conclusions about the possible structure of these clusters as a function of size are drawn by comparison with recent experimental results. We find that for small clusters the preferred structure is mainly icosahedral while for larger sizes (N ≥ 30) the bcc structure begins to compete with the icosahedral one. The magnetic coupling within the clusters is non-ferromagnetic. © 2003 WILEY-VCH Verlag GmbH %26 Co. KGaA, Weinheim.

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