A transmission electron microscopy study of CoFe2O4 ferrite nanoparticles in silica aerogel matrix using HREM and STEM imaging and EDX spectroscopy and EELS

Falqui, A. and Corrias, A. and Wang, P. and Snoeck, E. and Mountjoy, G. (2010) A transmission electron microscopy study of CoFe2O4 ferrite nanoparticles in silica aerogel matrix using HREM and STEM imaging and EDX spectroscopy and EELS. Microscopy and Microanalysis, 16 (2). pp. 200-209. ISSN 1431-9276. (doi:https://doi.org/10.1017/S1431927610000061) (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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Official URL
http://dx.doi.org/10.1017/S1431927610000061

Abstract

Magnetic nanocomposite materials consisting of 5 and 10 wt% CoFe 2O4 nanoparticles in a silica aerogel matrix have been synthesized by the sol-gel method. For the CoFe2O4-10wt% sample, bright-field scanning transmission electron microscopy (BF STEM) and high-resolution transmission electron microscopy (HREM) images showed distinct, rounded CoFe2O4 nanoparticles, with typical diameters of roughly 8 nm. For the CoFe2O4-5wt% sample, BF STEM images and energy dispersive X-ray (EDX) measurements showed CoFe2O4 nanoparticles with diameters of roughly 3 ± 1 nm. EDX measurements indicate that all nanoparticles consist of stoichiometric CoFe2O4, and electron energy-loss spectroscopy measurements from lines crossing nanoparticles in the CoFe2O4-10wt% sample show a uniform composition within nanoparticles, with a precision of at best than ± 0.5 nm in analysis position. BF STEM images obtained for the CoFe2O 4-10wt% sample showed many "needle-like" nanostructures that typically have a length of ? 10 nm and a width of ? 1 nm, and frequently appear to be attached to nanoparticles. These needle-like nanostructures are observed to contain layers with interlayer spacing 0.33 ± 0.1 nm, which could be consistent with Co silicate hydroxide, a known precursor phase in these nanocomposite materials.

Item Type: Article
Uncontrolled keywords: CoFe2O4, EDX, EELS, Ferrite, HREM, Nanoparticles
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 11:49 UTC
Last Modified: 04 Dec 2017 12:37 UTC
Resource URI: https://kar.kent.ac.uk/id/eprint/46212 (The current URI for this page, for reference purposes)
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