Dresden 2011 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 12: Postersitzung I
MM 12.49: Poster
Montag, 14. März 2011, 17:30–19:00, P5
Electron holography of Fe nanoparticles embedded in MgO crystals — •Dorin Geiger1, Hannes Lichte1, Artem Shalimov2, and Kay Potzger2 — 1Technische Universitaet Dresden, ISP, Triebenberglabor, Zum Triebenberg 50, 01328 Dresden, Germany — 2Institute of Ion Beam Physics and Materials Research, Forschungszentrum Dresden-Rossendorf, Bautzner Landstrasse 400, 01328 Dresden, Germany
In Mg-oxide embedded iron nanoparticles [1] show relevant magnetic fields being epitaxially related to the surrounding matrix. Their properties as nano-dimensional objects can strongly differ from those of the macroscopic ones, due to large surface to volume ratios. They were synthesized by Fe+ ion implantation at an energy of 100keV (incidence angle 7∘) with varying fluences up to 3×1017 cm2. Both alfa-Fe (body centered cubic) and gamma-Fe nanoparticles (face centered cubic) are formed in a surface layer of about 50nm thickness. The content of the alfa-Fe phase, which seems to be responsible for the magnetic behaviour, increases at higher fluences and after annealing [1].
To investigate the magnetic fields at nano-scale, off-axis electron holography was applied using a Cs-corrected transmission electron microscope (Tecnai F20 Cs-corr) [2] working in a pseudo Lorentz mode. This allows the reconstruction of the object wave phase, which can be interpreted quantitatively in terms of electromagnetic fields.
[1] Shalimov, A. et al., Journal of Applied Physics 105, 064906 (2009)
[2] Geiger, D. et al., Microsc. Microanal. (2008) 14, 68-81.
Funding by DFG.