Magnetic and structural investigation of highly porous CoFe 2O4-SiO2 nanocomposite aerogels

Casu, A. and Casula, M.F. and Corrias, A. and Falqui, A. and Loche, D. and Marras, S. (2007) Magnetic and structural investigation of highly porous CoFe 2O4-SiO2 nanocomposite aerogels. Journal of Physical Chemistry C, 111 (2). pp. 916-922. ISSN 1932-7447. (doi:https://doi.org/10.1021/jp0650230) (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/10.1021/jp0650230

Abstract

The structural and magnetic properties of CoFe2O 4-SiO2 nanocomposite porous aerogels have been systematically investigated by XRD, TEM, and SQUID magnetometry. The preparation of the samples was performed by a cogelation sol-gel route which allows one to obtain nanocomposites with high purity and homogeneity and to control the composition of the sample in terms of ferrite loading in the nanocomposite. In particular, the compositional effect on both the structural and magnetic properties of the nanocomposite was investigated in two nanocomposites with relative CoFe2O4 amounts of 5 and 10 wt %. The characterization shows both similarities and differences in the structural evolution of the nanophases within the amorphous porous matrix of the two nanocomposites as a function of the calcination temperature. In both samples the ferrite nanoparticles are formed above 750 °C; however, a slower structural evolution is observed in the nanocomposites with 5 wt % CoFe2O 4. The nanocomposites display superparamagnetic behavior with blocking temperature that increases with both the ferrite amount and the calcination temperature. The importance of combining information from different techniques is also discussed, with particular reference to nanocrystal size determination. The results provide insights into the characterization of innovative materials and on how the compositional and microstructural features affect the properties of magnetic nanocomposites.

Item Type: Article
Uncontrolled keywords: Cobalt compounds, Magnetic properties, Nanocomposites, Sol-gel process, SQUIDs, Structural properties, Blocking temperature, Calcination temperature, Compositional effects, Nanocomposite porous aerogels, Aerogels
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: 16 Dec 2014 15:15 UTC
Last Modified: 04 Dec 2017 12:40 UTC
Resource URI: https://kar.kent.ac.uk/id/eprint/46176 (The current URI for this page, for reference purposes)
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