Magnetic and Mössbauer Spectral Study of Core/shell Structured Fe/Au Nanoparticles

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 Mössbauer spectral studies. The powder X-ray diffraction patterns reveal both the presence of crystalline α-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 Mössbauer 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 α-iron and the unexpected amorphous Fe 1-xB x 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 than had been believed.

Department(s)

Chemistry

Sponsor(s)

Alfred P. Sloan Foundation
American Chemical Society
National Science Foundation of Belgium
Ministere de la Region Wallonne
National Science Foundation (U.S.)
University of California (System)

Keywords and Phrases

Power X-ray Diffraction Patterns; Reverse Micelles; Crystallization; Gold; Iron Alloys; Iron Oxides; Micelles; Mössbauer Spectroscopy; Synthesis (Chemical); X Ray Powder Diffraction; Nanostructured Materials; X-rays -- Diffraction

International Standard Serial Number (ISSN)

0897-4756

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2006 American Chemical Society (ACS), All rights reserved.

Publication Date

01 Feb 2006

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