Homogeneous Precipitation Synthesis and Magnetic Properties of Cobalt Ferrite Nanoparticles

Magnetic nanoparticles (NPs) of cobalt ferrite have been synthesized via a homogeneous precipitation route using hexamethylenetetramine (HMT) as the precipitant. The particle size, crystal structure, and magnetic properties of the synthesized particles were investigated by X-ray diffraction, transmission electron microscopy, and vibrating sample magnetometer. The NPs are of cubic inverse spinel structure and nearly spherical shape. With the increase of oxidation time from 30 to 180 minutes in the reaction solution at 90∘C, the average particle size increases from ~30 nm to ~45 nm. The as-synthesized NPs ~30 nm in size show higher Ms (61.5 emu/g) and moderate Hc (945 Oe) and Mr/Ms (0.45) value compared with the materials synthesized by coprecipitation method using NaOH as precipitate at high pH value.