Magnetism of small Mn clusters

JAVIER GUEVARA; ANA MARÍA LLOIS; F. AGUILERA-GRANJA; J.M.MONTEJANO=CARRIZALES

PHYSICA STATUS SOLIDI B-BASIC RESEARCH

WILEY-V C H VERLAG GMBH

Lugar: Weinheim; Año: 2003 vol. 239 p. 457 - 462

0370-1972

The role of structure on the magnetic properties of Mn clusters is investigated by performing calculations for different growth families, icosahedral, bcc and fcc. 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 whilefor larger sizes (N >30) the bcc structure begins to compete with the icosahedral one. The magnetic coupling within the clusters is non-ferromagnetic.