Synthesis and Characterization of Co–Zn Ferrite Nanoparticles by Hydrothermal Method: A Comparative Study

Well-crystallized cobalt-zinc ferrite (Co_0.6Zn_0.4Fe₂O₄) nanoparticles have been synthesized by four different hydrothermal routes, where two raw materials (NaBH₄ and NaOH) and mixing methods (magnetic stirring and colloid mill) are used. The microstructure, particle morphology, and magnetic property of the as-synthesized four samples are characterized by X-ray diffraction (XRD), Raman spectrum, scanning electron microscopy (SEM), and vibrating sample magnetometer. XRD patterns reveal that the as-prepared samples are pure spinel phase and good crystallinity. XRD analyses indicate that the substitution of NaBH₄ for NaOH leads to the increase in crystallite size of the ferrite nanoparticles, which can be confirmed by SEM images. In addition, using NaBH₄ and colloid mill during the hydrothermal process, the ferrite nanoparticles can obtain relatively higher saturation magnetization. This paper points out that as to hydrothermal synthesis, the choice of the raw material and mixing method has great effects on the properties of the prepared ferrite nanoparticles.