Dresden 2009 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 31: Magnetic Particles and Clusters I
MA 31.4: Vortrag
Donnerstag, 26. März 2009, 11:00–11:15, HSZ 401
Surprising insensitivity of the orbital magnetism in L10 ordered FePt nanoparticles to surface modifications by Al — •Carolin Antoniak1, Marina Spasova1, Anastasia Trunova1, Florian Römer1, Bernhard Krumme1, Markus E. Gruner1, Tobias Umbach2, Adham Amyan2, Kai Fauth2, and Heiko Wende1 — 1Fachbereich Physik, Universität Duisburg-Essen, D-47048 Duisburg — 2Physikalisches Institut, Universität Würzburg, D-97074 Würzburg
FePt nanoparticles in the chemically ordered L10 state are the subject of intense research activities driven both by fundamental interest and technological perspective.
In this work, the influence of an Al cap layer on the magnetism of pure metallic L10 FePt nanoparticles of different sizes between 6nm and 2nm in diameter is studied by means of x-ray absorption spectroscopy and its associated magnetic circular dichroism (XMCD) at the Fe L3,2 absorption edges. It was found that the net magnetisation at the Fe sites is reduced significantly with respect to the non-capped particles. The ratio of orbital-to-spin magnetic moment remains largely unchanged indicating that the enhanced orbital magnetism reported earlier [1,2] is not affected by an Al cap layer. The experimental results will be compared to recent ab-initio calculations for chemically ordered FePt clusters covered by an additional Al layer.
Financially supported by the DFG (SFB445 and SPP1239), the BMBF (05 ES3XBA/5), and the ESRF.
[1] C. Antoniak et al., Phys. Rev. Lett. 97, 11201 (2006)
[2] O. Dmitrieva et al., Phys. Rev. B 76, 064414 (2007)