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MA: Fachverband Magnetismus

MA 21: Poster I

MA 21.85: Poster

Dienstag, 13. März 2018, 09:30–13:00, Poster A

Monte-Carlo simulation studies on interacting 3D nanoparticle supercrystals — •Mauricio Cattaneo, Michael Smik, Oleg Petracic, and Thomas Brückel — Jülich Centre for Neutron Science JCNS and Peter Grünberg Institut PGI, JARA-FIT, Forschungszentrum Jülich GmbH, 52425 Jülich

The assembly of magnetic nanoparticles into large 3D structures constitutes a novel way of fabricating artificial materials that show properties that are not found in conventional systems. A detailed understanding of the magnetic properties is impeded by the huge number of contributing parameters as well as the difficulty in probing the internal magnetic structure in situ. Monte-Carlo Simulations offer the possibility to predict numerically possible magnetic low energy states. Sufficiently small nanoparticles can be considered as single domain, which may be modelled as an effective superspin. In contrast to atomic spins, the dominating inter-particle interaction is the dipole-dipole interaction. We simulated iron oxide nanoparticles in a fcc superlattice structure with various lattice constants in order to tune the interaction strength. An Onsager-like mean-field approach has been implemented in order to increase the performance of the basic Metropolis scheme. In the limit of vanishing magnetocrystalline anisotropy, several low-energy states but no unique ground state have been observed.