Berlin 2012 – scientific programme
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MA: Fachverband Magnetismus
MA 8: Magnetic Particles / Clusters I
MA 8.5: Talk
Monday, March 26, 2012, 18:45–19:00, EB 202
Tunable colloidal superlattice growth modes using iron oxide nanoparticles — •David Greving1, Oleg Petracic1, Durga Mishra1, Giovanni A. Badini Confalonieri1, Jan Perlich2, Boris P. Toperverg1, and Hartmut Zabel1 — 1Institut für Experimentalphysik/Festkörperphysik, Ruhr-Universität Bochum, 44780 Bochum — 2HASYLAB at DESY, Notkestrasse 85, 22603 Hamburg
The self-organization of nanoparticles (NPs) shows a comparable behavior to the crystalline growth of atoms. Therefore, systematically investigating those parameters influencing the colloidal growth is an important task when aiming at novel magnetic or electronic materials composed from NPs. To this end we employed two different self-assembly techniques, i.e. spin-coating and sedimentation of chemically synthesized iron oxide NPs with a mean diameter of 20 nm. We used various substrates, i.e. Si, Si with thermal oxide, Si with PMMA coating, Al, Al2O3 and MgO, to specifically influence the particle-to-substrate forces, thus tuning one of the main factors determining the corresponding growth mode. We were able to observe all three NP growth modes analogous to that found in classical thin film growth, i.e. Vollmer-Weber-, Frank-v.d.-Merwe- and Stranski-Krastanov. The systems are structurally and magnetically characterized using scanning electron microscopy, grazing incidence small angle x-ray scattering (GISAXS) and superconducting quantum interference device magnetometry, respectively.