Abstract
In this study, we report the synthesis and characterization of the core–shell Fe covered with Au shells nanoparticles with
mean diameters between 5 and 8 nm. The inverse micelles method was utilized to produce the samples. X-ray diffraction studies
show that both core–shell systems have the expected crystalline structure. High resolution transmission electron microscopy
and atomic emission spectroscopy techniques give additional information concerning the structure and composition of nanoparticles.
An intermediate shell of amorphous oxidized iron was found between the magnetic Fe core and the external gold shell. The magnetic
behavior of different core–shell samples shows no hysteresis loop indicating the superparamagnetic behavior of Fe@Au systems.
The superparamagnetic behavior is also evidenced from FC and ZFC dependences of the magnetization versus temperature. By using
the temperature dependence of the thermoremanent magnetization combined with magnetization versus applied magnetic field,
the effective anisotropy constant was determined. The Fe/Au interface contribution to the effective anisotropy constant was
calculated and discussed in relation with the combined shape and stress anisotropies.
mean diameters between 5 and 8 nm. The inverse micelles method was utilized to produce the samples. X-ray diffraction studies
show that both core–shell systems have the expected crystalline structure. High resolution transmission electron microscopy
and atomic emission spectroscopy techniques give additional information concerning the structure and composition of nanoparticles.
An intermediate shell of amorphous oxidized iron was found between the magnetic Fe core and the external gold shell. The magnetic
behavior of different core–shell samples shows no hysteresis loop indicating the superparamagnetic behavior of Fe@Au systems.
The superparamagnetic behavior is also evidenced from FC and ZFC dependences of the magnetization versus temperature. By using
the temperature dependence of the thermoremanent magnetization combined with magnetization versus applied magnetic field,
the effective anisotropy constant was determined. The Fe/Au interface contribution to the effective anisotropy constant was
calculated and discussed in relation with the combined shape and stress anisotropies.
- Content Type Journal Article
- Pages 1-12
- DOI 10.1007/s11051-011-0313-3
- Authors
- C. Leostean, National Institute for R&D of Isotopic and Molecular Technologies, P. O. Box 700, 400293 Cluj-Napoca, Romania
- O. Pana, National Institute for R&D of Isotopic and Molecular Technologies, P. O. Box 700, 400293 Cluj-Napoca, Romania
- R. Turcu, National Institute for R&D of Isotopic and Molecular Technologies, P. O. Box 700, 400293 Cluj-Napoca, Romania
- M. L. Soran, National Institute for R&D of Isotopic and Molecular Technologies, P. O. Box 700, 400293 Cluj-Napoca, Romania
- S. Macavei, National Institute for R&D of Isotopic and Molecular Technologies, P. O. Box 700, 400293 Cluj-Napoca, Romania
- O. Chauvet, Institute of Materials Jean Rouxel, 44322 Nantes cedex 3, France
- C. Payen, Institute of Materials Jean Rouxel, 44322 Nantes cedex 3, France
- Journal Journal of Nanoparticle Research
- Online ISSN 1572-896X
- Print ISSN 1388-0764
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