Effect of Reaction pH on Characterization of Co-precipitated Cobalt ferrite Nanoparticles

Abstract

Cobalt ferrite (CoFe₂O₄) nanoparticles were prepared by a chemical coprecipitation method at different pH conditions from 10.1 to 13.5. The XRD results reveal that pure cobalt ferrite particles with the inverse spinel structure are only formed at pH values higher than 11. The average particle diameter increases from 11.9 to 15.8 nm as the pH of reaction is increased from 11.1 to 13.5. The obtained results indicate that the ferrite precipitation process proceeds via the formation of cobalt hydroxide and the particle size distribution of this precursor determines the final particle size.  It is found that with increasing the pH of reaction, the magnetization increases meanwile the coercive field decreases. All the samples synthesized at investigated pH values show ferrimagnetic behavior and highest magnetization up to 60 Oe at the highest pH.