Regensburg 2002 – wissenschaftliches Programm
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MA: Magnetismus
MA 9: Magnetische Partikel / Cluster
MA 9.1: Vortrag
Dienstag, 12. März 2002, 14:00–14:15, H22
Magnetic properties of small clusters and wires on metallic surfaces — •Bence Lazarovits1, László Szunyogh1,2, and Peter Weinberger1 — 1Center for Computational Materials Science, Technical University of Vienna, Getreidemarkt 9/158, A-1060 Vienna, Austria — 2Department of Theoretical Physics, Budapest University of Technology and Economics, Budafoki út 8, H-1521, Budapest, Hungary
We present first principles calculations of the magnetic moments and magnetic anisotropy energies of small Fe, Co and Ni clusters on top of a Ag(100) surface. The calculations are performed fully relativistically using the embedding technique within the Korringa–Kohn–Rostoker method. In the case of adatoms and dimers of iron and cobalt we obtain enhanced spin moments and, especially, unusually large orbital moments, while for nickel our calculations predict a complete absence of magnetism. For larger clusters, the magnitudes of the calculated local moments imply a gradual onset of monolayer magnetism. Similar to the orbital moments, the contributions of the individual atoms to the magnetic anisotropy energy strongly depend on the position, hence, on the local environment of a particular atom within a given cluster.
We also investigated magnetic properties of finite linear chains of Co and Fe on and embedded in a Pt(111) surface. While enhanced moments characterize the atoms at the edges of the wires, for the inner atoms we observe typical oscillations with respect to the size of the wire, in particular, for the orbital moments, which are different in shape for even or odd number of atoms in the wire.