Dissertation > Industrial Technology > Electrotechnical > Electrical materials > Magnetic materials,ferrite > Ferrite,oxide magnetic materials

The Investigation of Dielectric and Magnetic Properties for Ti-doped Ni-Zn Ferrites

Author ZhangXianLiang
Tutor FengShuangJiu
School Anhui University
Course Materials Physics and Chemistry
Keywords dielectric material dielectric constant dielectric loss magneticconductivity magnetic loss
Type Master's thesis
Year 2012
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Soft magnetic ferrite material which is a kind electronic functional material has been widely used, and its magnetic has been paid attention in practical research and application. In fact soft magnetic ferrite material is not only magnetic medium, but also dielectric medium, and the latter which is studied because of its minor nature is ignored in research and application generally. If Soft magnetic material which is considered as high magnetic dielectric material has good dielectric properties, its application in electronic field will be important, the magnetic device not only can be built, but also the dielectric devices can be designed. If we can just consider it as material and develop a new type of magnetoelectricity composite material which has capacitance and inductance function can provide a possible way to solve the electronic components to miniaturization, high performance and high reliability. But according to the current research results, the study of dielectric properties of soft magnetic material is not enough deep and systemic. In order to realize such application level, the dielectric properties remain to be further improved. Meanwhile, the main influencing factors of dielectric material on its dielectric properties and producing the physical mechanism of dielectric properties are also needed to be enhanced deeply.In the paper, the traditional solid reaction is taken to prepared materials such as Ni0.2Zn0.8Fe2-xTix04(x=0,0.05,0.1,0.2,0.4) and Nio.4Zno.6Fe1.95Ti0.05, and we also study the effects of Ti on the structure of Ni ferrite crystal by X-ray diffraction device, and Wayne Kerr6500type B precision impedance analyzer is used to test its ceramic dielectric properties, especially for the effects of low temperature environment on the dielectric properties of the material, and AV3691rf impedance/material is used to study the dielectric properties in ratio-frequency band and BH analyzer is used to study the magnetic properties.XRD results show that only when the sintering temperature is higher than1265℃, Ti can be completely sent into the grid and partly replaced by ion Fe, and we also find that as component Nio.4Zno.6Fe2-xTixO4of Ti ion content increases, samples of the miscellaneous phase content becomes more and more.Wayne Kerr6500type B precision impedance analyzer test results indicate that the proportion of ions Zn and Ni of the sample will have effects on dielectric constant and dielectric loss. The dielectric constant is increasing with decreasing the ion Ni, and meanwhile, it will increase dielectric loss. But when the frequency is larger than5000Hz, the influence of the proportion of ions Zn and Ni of the sample will be very weak. In order to improve the dielectric properties and decrease the dielectric loss, the proportion of ion Ni of the sample should be kept small.The influence of low temperature on dielectric properties shows that the rotation of the inherent dipole moment will be frozen under the low temperature, so there is no contribution to dielectric constant. When temperature is increasing, the inherent dipole moment will be twirled by thermal excitation, the corresponding dielectric constant will be increasing, and dissipation factors of the material will produce a significant relaxation loss peak. Furthermore, as the test frequency increasing, the corresponding energy of the inherent dipole moment twirl will be increasing, too. So the increase of the dielectric constant and the loss of dielectric relaxation tangent will be moving to the high peak.The test results of AV3691show that mixing Ti into sample of Ni0.2Zn0.8Fe2O4will have effects on dielectric constant and dielectric loss, and we find mixing Ti can improve dielectric constant of sample of Ni0.2Zn0.8Fe2O4and reduce its dielectric loss. But as the ratio of Ti increasing, the dielectric loss will also be increasing. In order to improve dielectric properties and reduce dielectric loss, we should mix tiny ion Ti into the sample under the comprehensive consideration.The test results of BH analyzer indicate that the coefficients of magnetic hysteresis loss of low magnetic flux density are larger than high area, and the changed magnetic flux density is about4mT.

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