Dresden 2014 – scientific programme
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MA: Fachverband Magnetismus
MA 9: Magnetic Nanoparticles
MA 9.6: Talk
Monday, March 31, 2014, 16:30–16:45, HSZ 401
Magnetic proximity effects in nanoparticle-composite systems — •Genevieve Wilbs1, Oleg Petracic1, Emmanuel Kentzinger1, Joachim Gräfe2, Eberhard Goering2, and Thomas Brückel1 — 1Jülich Centre for Neutron Science JCNS and Peter Grünberg Institute PGI, JARA-FIT, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany — 2Max-Planck-Institute for Intelligent Systems, 70569 Stuttgart, Germany
In recent years, nanoparticle assemblies have shifted into the focus of scientific interest because they behave neither like bulk material nor correspond to isolated particles. Hence, they offer the possibility to fabricate 'artificial materials' with novel emerging physical properties for a broad range of applications. We report about the magnetic properties of self-assembled iron oxide nanoparticle superlattices. The particles have a diameter of 20 nm and are covered with an organic surfactant shell. By applying them onto a silicon substrate via spincoating, they form self-organized sub-monolayers. The lateral order is demonstrated by GISAXS (Grazing Incidence Small Angle X-ray Scattering) and SEM (Scanning Electron Microscope) studies. Using SQUID (Superconducting Quantum Interference Device) magnetometry, it is shown that the particles exhibit superspin glass behavior due to dipolar inter-particle interactions. If the organic matrix is exchanged by a polarizable metal like platinum, the superspin glass behavior is partially suppressed and the inter-particle interactions become dominated by the polarization of Pt.