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A Magnetic and Moessbauer Spectral Study of Core/Shell Structured Fe/Au Nanoparticles

Sung-Jin Cho·Ahmed M. Shahin·Gary J. Long·Joseph E. Davies·Kai Liu·Fernande Grandjean·Susan M. Kauzlarich
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Abstract

Fe/Au nanoparticles have been chemically synthesized through a reverse micelle reaction and investigated by both conventional and synchrotron based x-ray diffraction and by magnetic and Moessbauer spectral studies. The powder x-ray diffraction patterns reveal both the presence of crystalline alpha-iron and gold and the absence of any crystalline iron oxides or other crystalline products. First-order reversal curves, along with the major hysteresis loops of the Fe/Au nanoparticles have been measured as a function of time in order to investigate the evolution of their magnetic properties. The iron-57 Moessbauer spectra of both uncoated iron nanoparticles and the Fe/Au nanoparticles have been measured at 78 and 295 K and indicate that two major iron containing components are present, namely the expected alpha-iron and the unexpected amorphous Fe1-xBx alloy; several poorly crystallized ordered iron(III) oxide components as well as paramagnetic iron(II) and iron(III) components are also observed. These results indicate that the Fe-core/Au-shell nanoparticles synthesized through reverse micelles are far more complex that had been believed.

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Sung-Jin Cho, Ahmed M. Shahin, Gary J. Long, Joseph E. Davies, Kai Liu, Fernande Grandjean, Susan M. Kauzlarich. 2005-12-16. A Magnetic and Moessbauer Spectral Study of Core/Shell Structured Fe/Au Nanoparticles. https://doi.org/10.1021/cm0522073

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