Ionic magnetic fluid based on cobalt ferrite nanoparticles: Influence of hydrothermal treatment on the nanoparticle size

Magnetic fluid based on cobalt ferrite nanoparticles was obtained using a hydrothermal treatment added to the Massart procedure. This treatment increases the average size of the nanoparticles from 11.9 to 18.7 nm and also improves the dispersity and crystallinity of the cobalt ferrite particles. The nanoparticles obtained after the hydrothermal treatment were dispersed in aqueous solvent by the classical procedure for ionic magnetic fluids. The ferrofluid thus obtained is stable at pH 7 and may be useful for hyperthermia applications.

Research Highlights
► Hydrothermal synthesis of cobalt ferrite ferrofluid (mean particle size of 12–19 nm).
► Good control of size, dispersity and crystallinity of the cobalt ferrite particles.
► Ferrofluid stable at pH 7 and useful for hyperthermia applications.