E. M. Sosa-Hernández¹, P. G. Alvarado-Leyva²

¹ Departamento de Matemáticas Aplicadas, Facultad de Contaduría y Administración, Universidad Autónoma de San Luis Potosí, Álvaro Obregón 64, 78000 San Luis Potosí, S.L.P. México

² Departamento de Física, Facultad de Ciencias, Universidad Autónoma de San Luis Potosí, Álvaro Obregón 64, 78000 San Luis Potosí, S.L.P. México

Recibido: 29 de diciembre de 2006.
Aceptado: 8 de febrero de 2007.

Abstract

The magnetic behavior of clusters Cr₆-Cr₉ in bulk Fe is determined by using an electronic Hamiltonian which includes s, p and d electrons. The spin density distribution is calculated self-consistenly in the unrestricted Hartree-Fock approximation. The local magnetic moments μ (i) are obtained at various atoms i of Cr clusters and of the surrounding matrix. The local magnetic moments at Fe atoms and the magnetic moments of Cr atoms present an antiparallel coupling. The magnetic behavior of Cr clusters depends on two factors, the size of the cluster and the proximity between them. For Cr₆ the magnetic moments at Cr atoms are parallel whereas for Cr₉ the μ_Cr(i) are antiparallel. The magnetic order in the matrix is not broken by the presence of the Cr atoms, but the local magnetic moments of Fe atoms in the interface cluster-matrix are reduced respect to Fe bulk magnetization. [v.g. μ_Fe(5')=2μ_B in Cr₆; μ_Fe(3)=1.8μ_B in Cr₉].

Keywords: Local magnetic moments; Magnetic order; Magnetic frustrations.

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