Berlin 2005 – wissenschaftliches Programm
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MA: Magnetismus
MA 4: Mikromagnetismus / Computational Magnetism
MA 4.1: Vortrag
Freitag, 4. März 2005, 12:00–12:15, TU H1028
Exact parametrization of the adiabatic magnetic energy hypersurface — •Ralf Drautz1,2 and Manfred Fähnle1 — 1Max-Planck-Institut für Metallforschung, Heisenbergstraße 3, 70569 Stuttgart, Germany — 2Department of Materials, University of Oxford, OX1 3PH, UK
The complexity of magnetic interactions in nanostructured magnetic systems makes it necessary to establish a parameter-free multi-scale framework for modelling. First-principles-based dynamics and statistical mechanics for magnetic systems thereby require an accurate and sufficiently general but at the same time computationally efficient representation of the adiabatic magnetic energy of many interacting atoms. We exactly parameterize the adiabatic magnetic energy of generalized interacting spins for the important special case of zero spin-orbit coupling and no applied external field. The expansion classifies the classical Heisenberg model as a first order approximation to the energy, extensions of the Heisenberg model in literature are shown to be of second order. We relate the symmetry-based energy expansion presented in this talk to the more general spin-cluster expansion that we published recently [1].
[1] R. Drautz and M. Fähnle, Phys. Rev. B 69, 104404 (2004)