Regensburg 2010 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 41: Poster Session I (Semiconductor Substrates: Epitaxy and growth; Semiconductor Substrates: Adsorbtion; Semiconductor Substrates: Solid-liquid interfaces; Semiconductor Substrates: Clean surfaces; Oxides and insulators: Epitaxy and growth; Oxides and insulators: Adsorption; Oxides and insulators: Clean surfaces; Organic, polymeric and biomolecular films - also with adsorbates; Organic electronics and photovoltaics, Surface chemical reactions; Heterogeneous catalysis; Phase transitions; Particles and clusters; Surface dynamics; Surface or interface magnetism; Electron and spin dynamics; Spin-Orbit Interaction at Surfaces; Electronic structure; Nanotribology; Solid/liquid interfaces; Graphene; Others)

O 41.75: Poster

Dienstag, 23. März 2010, 18:30–21:00, Poster B1

Spin dynamics of Co nano-islands on Cu(111) from first principles — •Danny Böttcher, Arthur Ernst, Ingrid Mertig, and Jürgen Henk — Max Planck Institute of Microstructure Physics, Halle, Germany

Co nano-islands on Cu(111) show a variety of interesting quantum phenomena. Concerning magnetism, the switching of the islands’ magnetizations by an external magnetic field has been investigated experimentally by STM [1]. The findings of these experiments can hardly by interpreted satisfactorily in terms of the Stoner-Wohlfarth model because the latter gives disputable numbers (e. g., too large an anisotropy constant). Hence, a microscopic model, with exchange and anisotropy parameters computed reliably from first principles, seems to be necessary.

Here, we present detailed calculations on the spin dynamics of Co nano-islands on Cu(111) within the framework of the Landau-Lifshitz-Gilbert equation with Langevin dynamics. The Heisenberg exchange parameters and the magnetocrystalline anisotropy have been computed from first principles, using our scalar-relativistic and relativistic KKR codes. We address in particular the behaviour of the islands’ spins under switching by an external magnetic field and the dependence of the switching fields on the island size.

[1] G. Rodary, S. Wedekind, D. Sander, and J. Kirschner, Jap. J. Appl. Phys. 47, 9013 (2008).