Reversible post-synthesis tuning of the superparamagnetic blocking temperature of gamma-Fe2O3 nanoparticles by adsorption and desorption of Co(II) ions
2007 (English)In: Journal of Materials Chemistry, ISSN 0959-9428, E-ISSN 1364-5501, Vol. 17, no 4, 322-328 p.Article in journal (Refereed) Published
The influence of the post-synthesis adsorption of Co(II) ions on the structural and magnetic properties of maghemite (gamma-Fe2O3) nanoparticles with a mean particle size of about 10 nm has been investigated. It is shown that the step-wise adsorption of Co( II) can controllably increase the blocking temperature, T-B, of the system up to 60 K with respect to that of untreated particles, while neither the particle size nor the particle size distribution are significantly modified. This is accompanied by a four-fold increase in the coercivity, H-C, at low temperatures. Using a selective leaching of the previously adsorbed Co(II) ions the T-B and H-C values of the pristine gamma-Fe2O3 nanoparticles are recovered. Hence, a reversible and controllable tailoring of the magnetic properties (e.g., T-B and H-C) of the gamma-Fe2O3 nanoparticles can be achieved by a simple adsorption and desorption process of Co( II) ions after their synthesis.
Place, publisher, year, edition, pages
2007. Vol. 17, no 4, 322-328 p.
iron-oxide, magnetic-properties, electron-transfer, particles, ferrite, fe2o3, co2+
IdentifiersURN: urn:nbn:se:kth:diva-16318DOI: 10.1039/b613026gISI: 000243387600003ScopusID: 2-s2.0-33846059815OAI: oai:DiVA.org:kth-16318DiVA: diva2:334360
QC 201005252010-08-052010-08-05Bibliographically approved