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O: Fachverband Oberflächenphysik

O 36: Poster Session II (Organic films and electronics, photoorganics; Nanostructures; Plasmonics and nanooptics, Surface chemical reactions and heterogeneous catalysis, Surface dynamics )

O 36.77: Poster

Dienstag, 12. März 2013, 18:15–21:45, Poster B2

Synthesis of core-shell and composite nanoparticles — •Aladin Ullrich, Stefan Hohenberger, and Siegfried Horn — Lehrstuhl für Experimentalphysik II, Universität Augsburg

We have investigated the synthesis of core-shell and composite transition metal oxide nanoparticles. The particles were synthesized by thermal decomposition of metallorganic precursors in a high-boiling solvent. We synthesized particles consisting of a mixture of iron oxide and manganese oxide in a two-step synthesis.

In the first step, iron oleate and manganese oleate were used as precursors for the production of pure iron oxide and manganese oxide nanoparticles, respectively. In the second step, these particles were used as seed crystals for the growth of the respective other compound. Following this route we were able to synthesize composite particles combining iron oxide and manganese oxide. The particles were characterized by transmission electron microscopy, using the energy filtered imaging mode to visualize the elemental distribution. The composite particles found included also core-shell-systems with a size of 20 nm.

The magnetic properties of the particles were studied on a sample produced by drying a solution of hexane containing composite particles. Field cooled magnetic hysteresis measurements show an exchange bias. We suggest that this exchange bias arises from the interface between manganese oxide and iron oxide within the composite particles.

The preparation method for composite nanoparticles described here is widely applicable, e.g. it can be applied to almost all transition metal oxides.