Regensburg 2016 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 39: Magnetic Particles

MA 39.2: Vortrag

Donnerstag, 10. März 2016, 09:45–10:00, H31

Structural and magnetic properties of self-assembled 3D nanoparticle macrocrystals — •Michael Smik, Genevieve Wilbs, Elisa Volkmann, Emmanuel Kentzinger, Jörg Persson, Ulrich Rücker, Oleg Petracic, and Thomas Brückel — Jülich Centre for Neutron Science JCNS and Peter Grünberg Institut PGI, JARA-FIT, Forschungszentrum Jülich GmbH, 52425 Jülich

We have used centrifuge assisted sedimentation to fabricate 3D nanoparticle ’macrocrystals’ from commercially available spherical iron oxide nanoparticles. The assembly of macrocrystals up to 300 µm in size was possible. The samples were characterized using scanning electron microscopy, which allowed for the identification of single crystals, which could then be isolated for further study. Using small angle x-ray scattering (SAXS) using the new in-house instrument ’GALAXI’ (Gallium Anode Low-Angle X-ray Instrument) the supercrystalline structure could be identified to be face-centered cubic. The magnetic structure was investigated by a variety of magnetometric methods, including zero field cooled and field cooled curves, thermo remanent and isothermal remanent magnetization, as well as ac susceptibility. All methods hint toward a spin-glass-like structure, however, deviations from the expected results for a spin-glass indicate a novel kind of magnetic ordering.