A transmission electron microscopy study of fe-Co alloy nanoparticles in silica aerogel matrix using HREM, EDX, and EELS

Falqui, A., Corrias, A., Gass, M., Mountjoy, G. (2009) A transmission electron microscopy study of fe-Co alloy nanoparticles in silica aerogel matrix using HREM, EDX, and EELS. Microscopy and Microanalysis, 15 (2). pp. 114-124. ISSN 1431-9276. (doi:10.1017/S1431927609090114) (The full text of this publication is not currently available from this repository. You may be able to access a copy if URLs are provided)

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http://dx.doi.org/10.1017/S1431927609090114

Abstract

Magnetic nanocomposite materials consisting of 5.5 wt% Fe-Co alloy nanoparticles in a silica aerogel matrix, with compositions FexCo1x of x = 0.50 and 0.67, have been synthesized by the sol-gel method. The high-resolution transmission electron microscopy images show nanoparticles consisting of single crystal grains of body-centered cubic Fe-Co alloy, with typical crystal grain diameters of approximately 4 and 7 nm for Fe0.5Co0.5 and Fe0.67Co0.33 samples, respectively. The energy dispersive X-ray (EDX) spectra summed over areas of the samples gave compositions FexCo1x with x = 0.48 0.06 and 0.68 0.05. The EDX spectra obtained with the 1.5 nm probe positioned at the centers of 20 nanoparticles gave slightly lower concentrations of Fe, with means of x = 0.43 0.01 and x = 0.64 0.02, respectively. The Fe0.5Co0.5 sample was studied using electron energy loss spectroscopy (EELS), and EELS spectra summed over whole nanoparticles gave x = 0.47 0.06. The EELS spectra from analysis profiles of nanoparticles show a distribution of Fe and Co that is homogeneous, i.e., x = 0.5, within a precision of at best 0.05 in x and 0.4 nm in position. The present microscopy results have not shown the presence of a thin layer of iron oxide, but this might be at the limit of detectability of the methods.

Item Type: Article
DOI/Identification number: 10.1017/S1431927609090114
Uncontrolled keywords: EDX, EELS, Fe-Co alloy, HREM, Nanoparticles, alloy, cobalt, iron, metal nanoparticle, silicon dioxide, article, chemistry, electron energy loss spectroscopy, evaluation, methodology, spectroscopy, transmission electron microscopy, ultrastructure, X ray, Alloys, Cobalt, Iron, Metal Nanoparticles, Microscopy, Electron, Transmission, Silicon Dioxide, Spectroscopy, Electron Energy-Loss, Spectrum Analysis, X-Rays
Subjects: Q Science > QC Physics > QC176.8.N35 Nanoscience, nanotechnology
Divisions: Faculties > Sciences > School of Physical Sciences > Functional Materials Group
Depositing User: Anna Corrias
Date Deposited: 17 Dec 2014 11:51 UTC
Last Modified: 29 May 2019 13:57 UTC
Resource URI: https://kar.kent.ac.uk/id/eprint/46214 (The current URI for this page, for reference purposes)
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