Regensburg 2013 – scientific programme
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DF: Fachverband Dielektrische Festkörper
DF 12: Poster 1
DF 12.31: Poster
Tuesday, March 12, 2013, 10:30–13:30, Poster D
Experimental investigation and modeling of the spin structure in FePt@MnO heterodimer nanoparticles — •Xiao Sun1, Alice Klapper1, Oleg Petracic1, Oskar Koehler2, Heiko Bauer2, Wolfgang Tremel2, and Thomas Brueckel1 — 1Jülich Centre for Neutron Science JCNS-2 und Peter Grünberg Institut PGI-4, Forschungszentrum Jülich GmbH — 2Institut für Anorganische und Analytische Chemie, Johannes Gutenberg-Universität Mainz
Magnetic nanoparticles (NPs) have attracted much interest for decades. We have focused on FePt@MnO heterodimer NPs consisting of a ferromagnetic FePt particle in contact to an antiferromagnetic MnO particle. Single FePt, single MnO and FePt@MnO dimer NPs with different sizes (5-20nm) have been studied using SQUID magnetometry employing zero field cooled (ZFC)/field cooled (FC) magnetization curves at various fields, hysteresis curves and thermoremanent (TRM)/ isothermoremanent (IRM) curves. An exchange bias effect in dimer particles has been observed by the shift of hysteresis loops at different temperatures suggesting a magnetic coupling between FePt and MnO. An exchange bias shift is not observed in single FePt or MnO NPs. Monte Carlo simulations of the spin structure in single MnO NPs and FePt@MnO dimer NPs are compared to the experimental findings. Neutron scattering experiments aiming to study the spin structure inside single MnO NPs and inside the MnO subunit of FePt@MnO heterodimers using polarized neutron diffraction are proposed.