| W-type ferrites have been used as permanent magnets for microwave devices,for high-density magnetic recording and for bubble domain memories in the form of thin monocrystalline layers due to their relatively strong anisotropy andmoderated magnetization.Fine-particle ferrites show magnetic properties diferent from sintered materials. A wide range of chemical methods in the solution such as sot-gel,chemical coprecipitation, glass crystallization method have been used to obtain ultrafine mixed particles. In comparision with the classical ceramic methods, these methods have many advantages as follows: They reduce reaction temperatures; There is a finer and more homogenous granulometry in the obtained ferrites; Magnetic properties have greatly been improved under the same sintered temperature. We have tried to synthesize W-type ferrite by citric acid method.We have tried to synthesize W-type ferrite and Fe-Ni nanoparticle composites by citric acid method We compose W-type ferrite and Fe-Ni nanoparticle composites into ferrite/ Fe-Ni nanoparticle composites.The samples were characterized by X-ray difraction(XRD) analys , transmission electron microscopy (TEM)The electromagnetic characteristics of te Fe ,Co ,Ni nanoparticles composites were measured by Agilent 8722ES microwave network analyzer in the band of 2～18 GHz..The experimental results show that the dopants of the Fe-Ni nanoparticle composites can alter microstructures and magnetic properties of W -typeFerrites,and the effects are much greatly. The dopants of the Fe-Ni nanoparticle composites can also increast the value ofμ″. While the ratio of Fe-Ni nanoparticle composites and W-type ferrite is 0.1, the effect is the greatest. |
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