Berlin 2012 – scientific programme
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DF: Fachverband Dielektrische Festkörper
DF 9: Poster I - Biomagnetism, FePt Nanoparticles, Magnetic Particles/Clusters, Magnetic Materials, Magnetic Semiconductors, Half-metals/Oxides, Multiferroics, Topological Insulators, Spin structures/Phase transitions, Electron theory/Computational micromagnetics, Magnetic coupling phenomena/Exchange bias, Spin-dependent transport, Spin injection/spin currents, Magnetization/Demagnetization dynamics, Magnetic measurement techniques
DF 9.12: Poster
Tuesday, March 27, 2012, 12:15–15:15, Poster A
Coupling behavior in iron-oxide nanoparticle/Py thin film composite systems — •Caroline Fink1, Philipp Szary1, Giovanni Badini Confalonieri1, Durgamadhab Mishra1, Maria Benitez1,2, Mathias Feyen2, An-Hui Lu2, Leonardo Agudo3, Gunther Eggeler3, and Oleg Petracic1 — 1Institut für Experimentalphysik/Festkörperphysik, Ruhr-Universität Bochum, D-44780 Bochum, Germany — 2Max-Planck-Institut für Kohlenforschung, D-45470 Mülheim an der Ruhr, Germany — 3Institut für Werkstoffe, Ruhr-Universität Bochum, D-44780 Bochum, Germany
We have investigated the magnetic and electrical transport properties of iron-oxide nanoparticle/Py thin film composite systems. Ultrathin films of Permalloy (Py) have been prepared by means of UHV ion beam sputtering and subsequently covered by one monolayer of iron-oxide nanoparticles. Post-annealing of the samples under controlled atmospheric conditions allows us to transform the particles into a mixed wüstite/magnetite (FexO/Fe3O4) phase showing intra-particle exchange bias. A slight variation of the NP type yields systems of different coupling behavior. Performing magnetometry and transport measurements we observe either a strong or weak coupling between the Py film and the NPs depending on the NP type. Moreover, a strongly decoupled behavior can be observed when adding a sapphire (Al2O3) layer separating the particles from the Py. Results have been compared with reference systems consisting of only NPs or only Py.