Berlin 2005 – wissenschaftliches Programm
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MA: Magnetismus
MA 31: Magnetische Partikel/Cluster II
MA 31.1: Vortrag
Mittwoch, 9. März 2005, 11:00–11:15, TU H1012
Electronic and Magnetic Properties of Arrays of well-separated fct FePt Nanoparticles Prepared using a Micellar Technique — •H.-G. Boyen1, A. Ethirajan1, U. Wiedwald1, F. Weigl1, G. Kästle1, P. Ziemann1, K. Fauth2, M. Heßler2, M. Büttner3, A. Romanyuk3 und P. Oelhafen3 — 1Abteilung Festkörperphysik, Universität Ulm, D-89069 Ulm — 2Experimentelle Physik IV, Universität Würzburg, Am Hubland, D-97074 Würzburg — 3Institut für Physik, Universität Basel, Klingelbergstr. 82, CH-4056 Basel
Arrays of colloidal FePt nanoparticles generally need to be annealed to elevated temperatures in order to achieve the desired, magnetically attractive, fct phase. Such heat treatment, however, is likely to result in the formation of larger agglomerates due to very small interparticle distances (few nanometers) of the as-deposited particle ensembles. Here, we present a new method allowing to prepare arrays of well separated and chemically pure FePt nanoparticles (diameter about 10 nm, interparticle distance about 100nm). These dots are synthesized by exploiting the selforganization of metal salt-loaded diblock copolymer reverse micells, followed by a plasma-induced removal of the polymer matrix after deposition of a micellar monolayer on a silicon substrate, leading to metallic nanodots in the chemically disordered fcc phase. These dots are then annealed to 650oC for 2 hours yielding the fct phase without any indication for sintering. X-ray induced photoelectron spectroscopy (XPS) and X-ray Magnetic Circular Dichroism (XMCD) are used to study the electronic and magnetic properties in detail after the different preparational steps. First results will be presented.