Berlin 2008 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 22: Magnetic Particles / Clusters II
MA 22.9: Vortrag
Mittwoch, 27. Februar 2008, 16:00–16:15, H 1028
Chemical trends in structure and magnetism of binary multiply twinned nanoparticles — •Markus Ernst Gruner, Antje Dannenberg, and Peter Entel — Fachbereich Physik, Universität Duisburg-Essen, 47048 Duisburg, Germany
Arrays of L10 ordered nanoparticles of near-stoichiometric FePt and
CoPt with diameters down to 4 nm are considered as promising
material for future ultra-high density recording media. However, with
decreasing particle size, also multiply twinned structures like decahedra and icosahedra are frequently encountered in experiment
(e. g., [1]).
These structures, however, will not posses the required hard magnetic
properties due to the different crystallographic orientations of the
individual twins. Recent large scale ab initio calculations of FePt clusters with up to 2.5 nm in diameter [2] show that ordered multiply twinned structures are energetically preferred over L10 cuboctahedra. Within this contribution, we discuss from the electronic structure point of view the influence of chemical trends on the structural stability of the L10 phase obtained by variation of the 3d and the 5d element.
[1] Z. R. Dai et al., Surf. Sci. 505, 325 (2002); D. Sudfeld et al., Mater. Res. Soc. Symp. Proc. 998E, 0998-J01-06 (2007)
[2] M. E. Gruner, G. Rollmann, P. Entel, M. Farle (submitted)