Controlled-Synthesis, Characterization And Properties Of Spinel Ferrite Nanocrystallines

The unusual electric and magnetic properties exhibited by spinel ferrite nanomaterials and their promising technological applications have attracted much interest. Both the intrinsic properties and applications of a ferrite nanoparticle are mainly determined by its size, morphologies, and chemical composition. Therefore, it is important to control any one of these parameters and understand the correlations between the material properties and its microstructure. In this paper, several representative spinel ferrite nanoparticles, including Fe₃O₄, Zn ferrite, BaZn ferrite, have been controlled fabricated via solvothermal method. The influence of both their sizes and shapes on the magnetic and/or electromagnetic properties has been studied. Valuable researches have been carried out to synthesize other binary and ternary spinel ferrite nanoparticles.Herein, we developed a simple and environmentally friendly solvothermal strategy for the synthesis of spherical-like and round-biscuit-like Fe₃O₄ nanocrysals. The particles sizes can be readily tuned in a wide range of 10-200 nm by adjusting some experimental conditions. The formation mechanism for Fe₃O₄ nanocrysals have been investigated in details. The influence of both its sizes and shapes on the magnetic and microwave adsorption properties has been studied.We presented a novel solvothermal method for spinel hollow Zn ferrites nanospheres with metal substitution by simply adding ZnCl₂ precursor to the system. In the sealed solvothermal reaction system, a great deal of bubble, serves as "soft" template to prepare the hollow nanospheres. Its sizes, shapes, and chemical compositions can be readily tuned by adjusting experimental conditions. The magnetic and microwave absorption properties of hollow Zn ferrite nanospheres and nanosheets were also investigated in detail and revealed that both magnetic and microwave absorption properties of the former are superior to those of the latter.The process to prepare Fe₃O₄ nanoparticles can also be readily extended to the exploring synthesis of other monodisperse binary ferrites, including Co ferrite, Mn ferrite, Ni ferrite, Cu ferrite, and Mg ferrite, via metal element substitution. The shapes of these nanoparticles are spherical-like and their sizes are in 10～250nm. The magnetic and/or microwave absorption properties of these five nanospheres were also investigated.Zinc complex ferrite nanosheets with Ba²⁺ substitution have been successfully synthesized via solvothermal method. Its shapes and sizes can be tuned by altering experimental parameters. BaZn ferrite with different shapes such as rod-like, spherical and other irregular have successfully fabricated and their sizes are in 8～120nm. The electric and electromagnetic properties for both monodisperse zinc ferrite nanospheres and its Ba substitutions nanosheets have been studied and revealed that saturation magnetization of BaZn ferrite is higher than that of Zn ferrite nanoparticles. Based on the same route, other monodisperse ternary spinel complex ferrites nanospheres, including MnZn ferrites, CuZn ferrites, NiZn ferrites, MgZn ferrites, and CoZn ferrites have been fabricated.