Reference : Spin excitations in cubic maghemite nanoparticles studied by time-of-flight neutron s...
Scientific journals : Article
Physical, chemical, mathematical & earth Sciences : Physics
http://hdl.handle.net/2268/182156
Spin excitations in cubic maghemite nanoparticles studied by time-of-flight neutron spectroscopy
English
Disch, S. [Jülich Centre for Neutron Science JCNS, Peter Grünberg Institut PGI, Forschungszentrum Jülich, D-52425 Jülich, Germany, Institut Laue-Langevin, F-38042 Grenoble, France]
Hermann, Raphaël mailto [Université de Liège > Département de chimie (sciences) > Département de chimie (sciences) >]
Wetterskog, E. [Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, S-10691 Stockholm, Sweden]
Podlesnyak, A. A. [Quantum Condensed Matter Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, United States]
An, K. [Center for Nanoparticle Research, Institute for Basic Science (IBS), Seoul 151-742, South Korea, School of Chemical and Biological Engineering, Seoul National University, Seoul 151-742, South Korea]
Hyeon, T. [Center for Nanoparticle Research, Institute for Basic Science (IBS), Seoul 151-742, South Korea, School of Chemical and Biological Engineering, Seoul National University, Seoul 151-742, South Korea]
Salazar-Alvarez, G. [Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, S-10691 Stockholm, Sweden]
Bergström, L. [Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, S-10691 Stockholm, Sweden]
Brückel, T. [Jülich Centre for Neutron Science JCNS, Peter Grünberg Institut PGI, Forschungszentrum Jülich, D-52425 Jülich, Germany]
2014
Physical Review. B, Condensed Matter and Materials Physics
89
6
Yes (verified by ORBi)
International
1098-0121
1098-0121
1550-235X
[en] We have determined the field dependence of collective magnetic excitations in iron oxide nanoparticles of cubic shape with 8.42(2) nm edge length and a narrow log normal size distribution of 8.2(2)% using time-of-flight neutron spectroscopy. The energy dependence of the uniform precession modes was investigated up to 5 T applied field and yields a Landé factor g=2.05(2) as expected for maghemite (γ-Fe2O3) nanoparticles. A large effective anisotropy field of BA,eff=0.45(16) T was determined, in excellent agreement with macroscopic measurements. This anisotropy is attributed to enhanced shape anisotropy in these monodisperse cubic nanoparticles. The combination of our results with macroscopic magnetization information provides a consistent view of the energy scales of superparamagnetic relaxation and collective magnetic excitations in magnetic nanoparticles. © 2014 American Physical Society.
http://hdl.handle.net/2268/182156
10.1103/PhysRevB.89.064402

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