Three kinds of spinel ferrite nanocrystals, MFe2O4 (M = Co, Ni, and Mn), are synthesized using colloid mill and hydrothermal method. During the synthesis process, a rapid mixing and reduction of cations with sodium borohydride (NaBH4) take place in a colloid mill then through a hydrothermal reaction, a slow oxidation and structural transformation of the spinel ferrite nanocrystals occur. The phase purity and crystal lattice parameters are estimated by X-ray diffraction studies. Scanning electron microscopy and transmission electron microscopy images show the morphology and particle size of the as-synthesized ferrite nanocrystals. Raman spectrum reveals active phonon modes at room temperature, and a shifting of the modes implies cation redistribution in the tetrahedral and octahedral sites. Magnetic measurements show that all the obtained samples exhibit higher saturation magnetization (Ms). Meanwhile, experiments demonstrate that the hydrothermal reaction time has significant effects on microstructure, morphologies, and magnetic properties of the as-synthesized ferrite nanocrystals.
Nanoparticles of Co0.6Zn0.4Fe2O4, with narrow size distribution, regular morphology, and high saturation magnetization, have been synthesized. The synthesis, involved a very rapid mixing of reducible metal cations with sodium borohydride, is carried out in a colloid mill and followed by a separate hydrothermal process. The microstructure and magnetic properties of the synthesized nanoparticles are characterized by X‐ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and vibrating sample magnetometer (VSM). The effects of different synthesis conditions (synthesis temperature and reaction time) on the characteristics of the ferrite nanoparticles are discussed. The changes in cation contribution are revealed by the Raman study. The magnetic measurements explore that all the as‐synthesized samples are superparamagnetic in nature. The corresponding superparamagnetic behavior is explained by paramagnetic Langevin theory. Note that, the superparamagnetic Co0.6Zn0.4Fe2O4 ferrite nanoparticle, with excellent performance, can be synthesized at 160°C for a short reaction time (4 h).
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.