Journal article
A neutron scattering study of spin precession in ferrimagnetic maghemite nanoparticles
We present inelastic neutron scattering studies of 4 nm maghemite nanoparticles. In applied magnetic fields (1-4 T) at 300 K, we observe a clear signal from collective magnetic excitations (spin precession of the whole particle moment). The precession is coherent since it is present at the antiferromagnetic wave vector transfer, 1.31 Å-1.
At high fields, the precession frequency varies linearly with field, corresponding to a Landé factor of g = 2.03(2). The intensity of the precession signal varies with temperature (in the range 6-300 K) and applied magnetic field in quantitative agreement with a simple thermodynamic model. The effective anisotropy field is estimated to 0.3(1) T.
Language: | English |
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Year: | 2001 |
Pages: | 526-532 |
ISSN: | 12864854 and 02955075 |
Types: | Journal article |
DOI: | 10.1209/epl/i2001-00279-7 |