Dresden 2014 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 9: Magnetic Nanoparticles
MA 9.1: Vortrag
Montag, 31. März 2014, 15:00–15:15, HSZ 401
Spin structure of MnO and FePt@MnO nanoparticles — •Xiao Sun1, Alice Klapper1, Yixi Su2, Kirill Nemkovski2, Andrew Wildes3, Oskar Koehler4, Heiko Bauer4, Anna Schilmann4, Wolfgang Tremel4, Oleg Petracic1, and Thomas Brueckel1 — 1Jülich Centre for Neutron Science JCNS-2 und Peter Grünberg Institut PGI-4, Forschungszentrum Jülich GmbH — 2Jülich Centre for Neutron Science JCNS Forschungszentrum Jülich GmbH, Outstation at MLZ — 3Institut Laue-Langevin, Grenoble, France — 4Institut für Anorganische und Analytische Chemie, Johannes Gutenberg-Universität Mainz
FePt@MnO heterodimer nanoparticles (NPs) are a novel type of multifunctional material.We have focused on the spin structure inside single MnO NPs and the influence of the exchange bias inside FePt@MnO heterodimer NPs onto the spin structure of MnO NPs. MnO NPs and FePt@MnO NPs with various sizes have been studied using SQUID magnetometry. The exchange bias effect has been observed in FePt@MnO NPs by the shift of hysteresis loops at different temperatures suggesting a magnetic coupling between FePt and MnO NPs. An exchange bias shift is also observed in single MnO NPs which is due to the coupling of the antiferromagnetic MnO core to a ferromagnetic Mn2O3 or Mn3O4 shell. The antiferromagnetic order parameter of MnO has been measured in both single MnO and FePt@MnO NPs using polarized neutron scattering. For comparison with the experimental findings, the spin structure inside single MnO NPs and FePt@MnO dimer NPs are simulated with Monte Carlo methods.