The Magnetic and Colloidal Properties of CoFe<sub>2</sub>O<sub>4</sub> Nanoparticles Synthesized by Co-precipitation

Authors

  • Sašo Gyergyek Department for Materials Synthesis, Jožef Stefan Institute, Jamova 39, SI-1000 Ljubljana, Slovenia
  • Miha Drofenik Department for Materials Synthesis, Jožef Stefan Institute, Jamova 39, SI-1000 Ljubljana, Slovenia Faculty of Chemistry and Chemical Engineering, University of Maribor, Smetanova 17, SI-2000 Maribor, Slovenia
  • Darko Makovec Department for Materials Synthesis, Jožef Stefan Institute, Jamova 39, SI-1000 Ljubljana, Slovenia

Keywords:

Cobalt ferrite, nanoparticles, co-precipitation, colloidal suspensions, magnetic properties

Abstract

Magnetic CoFe2O4 nanoparticles were synthesized by co-precipitation at 80 oC. This co-precipitation was achieved by the rapid addition of a strong base to an aqueous solution of cations. The investigation of the samples that were quenched at different times after the addition of the base, using transmission electron microscopy (TEM) coupled with energy-dispersive X-ray spectroscopy (EDXS) and X-ray powder diffractometry, revealed the formation of a Co-deficient amorphous phase and Co(OH)2, which rapidly reacted to form small CoFe2O4 nanoparticles. The nanoparticles grew with the time of aging at elevated temperature. The colloidal suspensions of the nanoparticles were prepared in both an aqueous medium and in a non-polar organic medium, with the adsorption of citric acid and ricinoleic acid on the nanoparticles, respectively. The measurements of the room-temperature magnetization revealed the ferrimagnetic state of the CoFe2O4 nanoparticles, while their suspensions displayed superparamagnetic behaviour.

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Published

04.09.2014

Issue

Vol. 61 No. 3 (2014)

Section

Materials science

License

Except where otherwise noted, articles in this journal are published under the Creative Commons Attribution 4.0 International License