Triethylene Glycol Stabilized CoFe2O4 Nanoparticles
2012 (English)In: Journal of Superconductivity and Novel Magnetism, ISSN 1557-1939, Vol. 25, no 6, 1879-1892 p.Article in journal (Refereed) Published
We report on the synthesis and detailed composition, thermal, micro-structural, ac-dc conductivity performance and dielectric permittivity characterization of triethylene glycol (TREG) stabilized CoFe 2O 4 nanoparticles synthesized by polyol method. XRD analysis confirmed the inorganic phase as CoFe 2O 4 with high phase purity. Microstructure analysis with TEM revealed well separated, spherical nanoparticles in the order of 6 nm, which is also confirmed by X-ray line profile fitting. FT-IR analysis confirms that TREG is successfully coated on the surface of nanoparticles. Overall conductivity of nanocomposite is approximately two magnitudes lower than that of TREG with increase in temperature. The ac conductivity showed a temperature dependent behavior at low frequencies and temperature independent behavior at high frequencies which is an indication of ionic conductivity. The dc conductivity of the nanocomposites and pure TREG are found to obey the Ar- rhenius plot with dc activation energies of 0.258 eV and 0.132 eV, respectively. Analysis of dielectric permittivity functions suggests that ionic and polymer segmental motions are strongly coupled in the nanocomposite. TREG stabilized CoFe 2O 4 nanoparticles has lower Îµ and Îµ than that of pure TREG due to the doping of cobalt. As the temperature increases, the frequency at which (Îµ ) reaches a maximum shifted towards higher frequencies. On the other hand, the activation energy of TREG for relaxation process was found to be 0.952 eV which indicates the predominance of electronic conduction due to the chemical nature of TREG. Contrarily, no maximum peak of tan ÎŽ was observed for the nanocomposite due to the being out of temperature and frequency range applied in the study.
Place, publisher, year, edition, pages
2012. Vol. 25, no 6, 1879-1892 p.
Chemical synthesis, Ionic conductivity, Magnetic materials, Magnetic properties, X-ray diffraction
IdentifiersURN: urn:nbn:se:kth:diva-101538DOI: 10.1007/s10948-012-1500-xISI: 000309157100040ScopusID: 2-s2.0-84864630946OAI: oai:DiVA.org:kth-101538DiVA: diva2:549607
QC 201209052012-09-052012-08-302012-11-05Bibliographically approved