Study of the Formation of Bimodal Distribution and Enhancement of Interparticle Magnetic Interactions in CoFe2O4 Nanoparticles with Increasing Hydrothermal Synthesis Time

We studied the effect of the duration of hydrothermal synthesis in the range from 8 to 12 h on the formation of the structural and magnetic properties of cobalt ferrite CoFe2O4 nanoparticles obtained in the presence of sodium dodecyl sulfate. It was shown that there is a transition from a unimodal particle distribution to a pronounced bimodal one, as well as an increase in crystallite sizes, microstrains, coercive force, and magnetic dipole–dipole interactions.