Study On The Preparation, Growth And Magnetic Properties Of Nano-MnZn Ferrite

MnZn ferrite is a kind of metal oxide soft magnetic functional material involving a wide range of applications.In the present of the rapid development of science and technology,with the development and research of the field of nano-materials,the new material with excellent performance and unique function has been developed.Nano-MnZn ferrite materials depend on quantum effect in micro-field and good magnetoelectric properties to open up a new way for its development and extend the application field of traditional sintered materials.In this paper,MnZn ferrite nanoparticles are prepared by hydrothermal and solvent methods.The reaction products are characterized by TEM,XRD,VSM.The magnetic properties and phase structure in hydrothermal/solvothermal environment are analyzed.The effects of reaction temperature and reaction time on the product were studied,and the growth modes of particles in different preparation environment were also studied and discussed.It is found that in the hydrothermal process,The formation of heterophase?-Fe₂O₃ after 1.5h of reaction.,and the maximum grain size of about 17.7nm is observed in the hydrothermal process for 3h.The highest OH^-consumption per unit time is 6.6×10^-3mol/h in the period of 0.5¹.5h.For solvothermal method,spinel can be formed at higher than 160?,but no heterophase can be formed only when it is higher than 180?,The grain size increases with temperature and reaction time,and the higher the content of Zn,the larger the grain size.The powder synthesized by both methods has the phenomenon of diffraction peak shift,but controlling the preparation of hydrothermal precursor at 60?and adjusting the pH value to 11 can effectively prevent the formation of heterophase and the shift of diffraction peak to the right.In addition,the Fe²⁺produced by the reduction of Fe³⁺by ethylene glycol is another main reason in solvothermal method.By fitting,we find that Fe³⁺:Fe²⁺is about 4:1.The existence of Fe²⁺makes the diffraction peak tend to Fe₃O₄.In addition,in the hydrothermal and solvothermal process,there is a growth process of crystal by OA mechanism,but the effect of OA mechanism on crystal growth is more obvious in solvothermal process.The higher pH in hydrothermal method is beneficial to the binding of suspended bonds between particles,which promotes the formation of OA and leads to the twin or single crystal growth of particles.The addition of CTAB could prevent the formation of organic layer on the surface of nanocrystals to prevent OA,from narrowing the particle size distribution.In solvothermal environment,nanocrystals can provide more opportunities for OA through ordered agglomeration,and the ability of OA is related to the content of Zn and the concentration of precursor.