Regensburg 2013 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 17: Magnetic Particles and Clusters (jointly with CPP, BP)
MA 17.4: Vortrag
Dienstag, 12. März 2013, 10:45–11:00, H22
Structural and Magnetic Properties of FePt@MnO Heterodimer Nanoparticles — •Alice Klapper1, Xiao Sun1, Oleg Petracic1, Ulrich Rücker1, Oskar Köhler2, Heiko Bauer2, Wolfgang Tremel2, and Thomas Brückel1 — 1JCNS-2 and PGI-4, Forschungszentrum Jülich GmbH — 2Institute of Inorganic Chemistry and Analytical Chemistry, Johannes Gutenberg University Mainz
On the length scale of few nanometers, surface effects are not negligible and therefore play an important role for the magnetic behavior of nanoparticles. In this work we investigate the magnetic properties of so-called FePt@MnO heterodimer nanoparticles, which consist of two exchange-coupled spherical nanoparticles, i.e. a ferromagnetic FePt and an antiferromagnetic MnO particle. The dimer nanoparticles have been precharacterized with respect to their structural properties via small angle x-ray scattering (SAXS) and a form factor model for particles consisting of two spherical subunits could be verified. This model has been proven by the anomalous SAXS (ASAXS) technique. The magnetic properties dependent on the size of the nanoparticles have been investigated with ZFC and FC measurements, using SQUID magnetometry. The exchange coupling could be proven by an exchange bias in hysteresis measurements as function of temperature. To investigate the ordering phenomenon the samples under study have been deposited on silicon substrates and dried with different applied magnetic fields. The dried samples have been studied using SEM and a chiral ordering of the heterodimer nanoparticles has been observed.