Bahl, Christian Robert Haffenden7; Hansen, Mikkel Fougt3; Pedersen, Thomas8; Nielsen, K.H.9; Saadi, Souheil4; Lebech, Bente4; Mørup, Steen4
1 Risø National Laboratory for Sustainable Energy, Technical University of Denmark2 Magnetic Systems, Department of Micro- and Nanotechnology, Technical University of Denmark3 Department of Micro- and Nanotechnology, Technical University of Denmark4 Department of Physics, Technical University of Denmark5 Nano-Microstructures in Materials, Materials Research Division, Risø National Laboratory for Sustainable Energy, Technical University of Denmark6 Materials Research Division, Risø National Laboratory for Sustainable Energy, Technical University of Denmark7 Department of Energy Conversion and Storage, Technical University of Denmark8 DTU Danchip, Technical University of Denmark9 unknown
We have studied the magnetic properties of 57Fe-doped NiO nanoparticles using Mössbauer spectroscopy and magnetization measurements. Two samples with different degrees of interparticle interaction were studied. In both samples the particles were characterized by high-resolution transmission electron microscopy and x-ray diffraction and found to be plate-shaped. Computer simulations showed that high-field Mössbauer data are very sensitive to the size of the uncompensated magnetic moment. From analyses of the Mössbauer spectra we have estimated that the size of the uncompensated magnetic moment is in accordance with a model based on random occupation of surface sites. The analyses of the magnetization data gave larger magnetic moments, but the difference can be explained by the different sensitivity of the two methods to a particle size distribution and by interactions between the particles, which may have a strong influence on the moments estimated from magnetization data.
Journal of Physics-condensed Matter, 2006, Vol 18, Issue 17, p. 4161-4175