This title appears in the Scientific Report : 2014 

Spin excitations in cubic maghemite nanoparticles studied by time-of-flight neutron spectroscopy
Wetterskog, E.
Podlesnyak, A. A. / An, K. / Hyeon, T. / Salazar-Alvarez, G. / Bergström, L. / Brückel, Th. / Hermann, Raphael / Disch, Sabrina (Corresponding author)
Streumethoden; JCNS-2
Streumethoden; PGI-4
Physical review / B, 89 (2014) 6, S. 064402
College Park, Md. APS 2014
Journal Article
In-house Research with PNI
Exploratory materials and phenomena
Spin-based and quantum information
Please use the identifier: in citations.
Please use the identifier: in citations.
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.