Dresden 2009 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 31: Magnetic Particles and Clusters I
MA 31.8: Vortrag
Donnerstag, 26. März 2009, 12:00–12:15, HSZ 401
Structure and magnetism of free and decorated Fe-Pt nanoclusters — •Markus Ernst Gruner and Peter Entel — Department of Physics and Center for Nanointegration CENIDE, University of Duisburg-Essen, 47048 Duisburg, Germany
Arrays of L10 ordered nanoparticles of near-stoichiometric Fe-Pt and Co-Pt with diameters are considered as promising material for future ultra-high density recording media due to the large magnetocrystalline anisotropy energy (MAE) in their bulk alloys. In small particles, the required magnetic properties are not realized in experiments. Possible reasons are the occurrence of multiply twinned morphologies which are frequently encountered in experiment and energetically preferred for small diameters as demonstrated in recent large scale ab initio calculations of Fe-Pt clusters [1,2] of up to 923 atoms. On the other hand, preparation of particles in a carbon matrix has been recently reported to support L10 order.
Within this contribution we present first principles structure optimizations
on the basis of density functional theory
of small Fe-Pt particles decorated with monolayers of typical covering
elements as gold, aluminum or carbon.
Based on these results, we discuss
the influence of a surrounding matrix on structural
and magnetic properties of small Fe-Pt nanoparticles, taking into account spin-orbit coupling and non-collinear spin-structures.
[1] M. E. Gruner, G. Rollmann, P. Entel and M. Farle,
Phys. Rev. Lett. 100, 087203 (2008).
[2] M. E. Gruner and P. Entel, Psi-k Newsletter 89, 36 (2008).