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Controlled cobalt doping in biogenic magnetite nanoparticles

DOI: 10.1098/rsif.2013.0134 DOI Help
PMID: 23594814 PMID Help

Authors: James Byrne (University of Manchester) , Vicky Coker (University of Manchester) , Sandhya Moise (Keele University) , P. L. Wincott (University of Manchester) , D. J. Vaughan (University of Manchester) , Floriana Tuna (University of Manchester) , Elke Arenholz (Advanced Light Source) , Gerrit Van Der Laan (Diamond Light Source) , Richard Pattrick (University of Manchester) , Jon Lloyd (University of Manchester) , Neil Telling (Keele University)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Journal Of The Royal Society Interface , VOL 10 , PAGES 20130134 - 20130134

State: Published (Approved)
Published: March 2013

Abstract: Cobalt-doped magnetite (CoxFe3-xO4) nanoparticles have been produced through the microbial reduction of cobalt-iron oxyhydroxide by the bacterium Geobacter sulfurreducens. The materials produced, as measured by superconducting quantum interference device magnetometry, X-ray magnetic circular dichroism, Mossbauer spectroscopy, etc., show dramatic increases in coercivity with increasing cobalt content without a major decrease in overall saturation magnetization. Structural and magnetization analyses reveal a reduction in particle size to less than 4 nm at the highest Co content, combined with an increase in the effective anisotropy of the magnetic nanoparticles. The potential use of these biogenic nanoparticles in aqueous suspensions for magnetic hyperthermia applications is demonstrated. Further analysis of the distribution of cations within the ferrite spinel indicates that the cobalt is predominantly incorporated in octahedral coordination, achieved by the substitution of Fe2+ site with Co2+, with up to 17 per cent Co substituted into tetrahedral sites.

Journal Keywords: coercivity; anisotropy; hyperthermia; Geobacter; Fe(III) reduction; X-ray magnetic; circular dichroism

Subject Areas: Environment

Facility: ALS