We report in this work the effects of the Polyvinylpyrrolidone (PVP) concentration on the solvothermal synthesis
of Fe₃O₄ nanocluster with different PVP concentrations such as 5 mg/ml, 10 mg/ml, and 25 mg/ml. The
effect of the PVP on the structural, microstructural, and magnetic properties was analyzed using different techniques.
XRD patterns showed the crystallization of all samples in the cubic structure with an average crystallite
size smaller than 10 nm. Homogeneous dispersion of the nanoparticles was shown for small concentrations
of PVP, while the aggregation of the nanoparticles was observed for higher concentrations leading to the formation
of uniform nanoclusters with an average size around 167 nm for a PVP concentration of 25 mg/ml. A
soft ferromagnetic behavior was found for all prepared samples with a saturation magnetization of about 54.75
emu/g obtained for Fe₃O₄ nanoparticles with 10 mg/ml of PVP.