Regensburg 2013 – scientific programme
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MA: Fachverband Magnetismus
MA 16: Poster I
MA 16.30: Poster
Tuesday, March 12, 2013, 10:30–13:30, Poster D
Individual and collective ferromagnetic resonance of 43 nm Fe/FexOy core/shell-nanocubes — •Alexandra Terwey, Ralf Meckenstock, Detelf Spoddig, Christian Schöppner, Marina Spasova, and Michael Farle — AG Farle, Experimentalphysik, Universität Duisburg Essen, Germany
Here we determine the magnetization, anisotropy and linewidth of 43 nm Iron/Ironoxide core/shell nanocubes, from a statistical distribution in solution over small agglomerates to single particles on a substrate. The nanocubes, surrounded by an organic matrix of ligands were produced according to a modified recipe of Kim et al. [1]. For the ferromagnetic resonance (FMR) a new technique with a microcavity set up has been used. This technique allows to investigate different configurations of particle arrangements and thereby to study in detail the effects of dipolar coupling. The microcavity FMR has a resolution of 106 spins [2]. The number of particles was continuously reduced until only single particles remained in the microcavity. FMR at room temperature with a frequency of 9 GHz shows single particle resonance with linewidths of 6 mT. We determined a magnetocrystalline anisotropy K4=(5±0,5)·103J/m3 which is only 10% of the Fe bulk value. The behaviour of single particles in comparison to a statistical distribution will be discussed on the poster. Financial support by MERCUR (PR-2011-0007) is acknowledged.
[1] Kim et al., JACS, 129, 5812-5813 (2007)
[2] Banholzer et al., Nanotech. 22, 295713 (2011)