Regensburg 2016 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 17: Poster Session I

MA 17.20: Poster

Dienstag, 8. März 2016, 09:30–12:30, Poster B1

Tuning the magnetic behavior of regular arrays of magnetic nanoparticles by their shape — •Alexander Fabian¹, Matthias T. Elm¹, Dieter Ehlers², Hans-Albrecht Krug von Nidda², and Peter J. Klar¹ — ¹I. Physikalisches Institut, Justus-Liebig-Universität Gießen, Heinrich-Buff-Ring 16, 35392 Gießen — ²Institut für Physik, UniversitätAugsburg, Universitätsstraße 1, 86159 Augsburg, Germany

Magnetite nanoparticles are a promising material for application in spintronic devices since magnetite possesses a very high spin polarization and a high Curie temperature. Reducing the size of the bulk material to the nanoscale may alter the magnetic properties e.g. nanoparticles will become superparamagnetic. Here, we present the characterization of the magnetic properties of regular arrays of magnetic nanoparticles with diameters of about 20 nm by FMR and SQUID measurements. Using a bottom-up process magnetic nanoparticles are arranged in regular arrays. Small openings with high lateral aspect ratios are defined in PMMA by e-beam lithography. Then the nanoparticles are self-assembled in the openings using the meniscus force deposition method. Angle dependent FMR measurements are performed. The resonance field shows a 180^∘-symmetry in both in-plane and out-of-plane configuration, which can be attributed to the elongated shape of the nanoparticle arrangements. SQUID measurements confirm a superparamagnetic behavior of the particles, but also exhibit differences in the magnetization in comparison to the typical superparamagnetic FC and ZFC curves of a circular thin film of nanoparticles.