Preparation And Magnetic Investigations Of NiZn-Ferrite Nanomaterials

In recent years, with the development of high-frequency communication signals, small and light weight of microelectronic devices, soft magnetic materials of high permeability, high saturation magnetization and high cutoff frequency make an urgent demands. NiZn ferrite is a widely used soft magnetic materials, its high frequency property is excellent, due to this reason, it has important applications in resistance to electromagnetic interference in electronic components. However, this material’s application frequency is low, which can not meet the development of high frequency communication needs. Nickel-zinc ferrite nanoparticles’s chemical composition, size distribution and particle morphology have an important influence on their magnetic properties, so by controlling the parameters(pH value, stoichiometric proportions, temperature and time) of nickel zinc ferrite nano materials’ preparation process to research the relationship of strcture and magnetic properties, have an important theoretical and practical significance to improve its performance on high-frequency noise suppression materials. In this paper, we study the morphology and magnetic properties of NiZn ferrite by studying different pH value, nickel/zinc ratio and temperature, using hydrothermal method. The main contents are as follows:1. Study the NixZn1-xFe2O4nanoparticle’s morphology and magnetic properties by hydrothermal method with different concentrations(x), the results show that:when x=0.6, it has the highest saturation magnetization, its average grain size is35nm, the shape of most particles is spherical, the saturation magnetization is64.93emu/g.2. Study pH value, surfactants, temperature’s effect on hydrothermal method though preparing NiZn ferrite nanoparticles. the results show that:when pH=10, it has the highest saturation magnetization, Ms=65.48emu/g. Adding PEG in hydrothermal reaction for preparing NiZn ferrite nanoparticles,which spheroidizes the nanoparticles. Adding Urea in hydrothermal reaction for preparing NiZn ferrite nanoparticles,which generates some fusiform nanoparticles, but the size distribution is non-uniform. Adding CTAB in hydrothermal reaction for preparing NiZn ferrite nanoparticles, which will make the particles size uniform, and generate some ellipsoid-shape nanoparticles. When the temperature between120℃-180℃, the lower hydrothermal reaction temperature seted, the smaller size particles got, and that, the smaller NiZn ferrite nanoparticles have lower saturation magnetization and higher coercivity.3. By select the right solution, we succeed put iron and NiZn ferrite nanoparticles together as composites by different volume ratio. The results show that:NiZn ferrite nanoparticles absorbed on the surface of iron and in the gap between two iron particles, that will decrease the conductive capability of iron efficiently, when the volume ratio (Viron/Vferrite) at the range of0-3, its saturation magnetization will increase notably, when the volume ratio larger than5:1, its saturation magnetization will be stable at the range of190-200emu/g.