posted on 2009-08-25, 13:56authored byO. Crisan, Klaus von Haeften, A. M. Ellis, C. Binns
Fe clusters have been synthesised in ultra-high-vacuum chamber using a gas-stabilized cluster aggregation method that ensures good control of the cluster size and naturally oxidized in order to obtain Fe/Fe oxide core-shell nanoparticles. The morphology of an individual nanoparticle, as revealed by transmission electron microscopy, consists of a Fe core of an average diameter of 4.4 nm surrounded by an oxide shell of uniform thickness of about 1.2 nm in average. The nanoparticles may be assimilated with a ferro-/antiferromagnetic (FM/AF) system. The morpho-structural features have been correlated with magnetic measurements on the core-shell nanoparticles. A significant exchange bias effect has been measured, when the sample was field-cooled under an applied field of 3 T. As the morphology of core-shell nanoclusters is much more complicated than in FM/AF bilayers of regular thickness due to the particular geometry of the coronal AF layer, the shape and surface anisotropy have to be taken into account for a correct interpretation of the magnetic data.
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Citation
Journal of Nanoparticle Research, 2008, 10 (supp.1), pp. 193-199.
This paper was published as Journal of Nanoparticle Research, 2008, 10 (supp.1), pp. 193-199. It is available from http://www.springerlink.com/content/y81518773424361n/ Doi: 10.1007/s11051-008-9463-3