| The continuous development of information society promotes the electronic components to the direction of small size, light weight, multi-functional and high stability. The development of magnetic materials and electronic materials has penetrated in all areas of modern technology, and the devices miniaturization trend has led to the development of multifunctional materials which can integrate electric and magnetic properties. Multiferroic material has not only a single ferroics (such as ferroelectricity, ferromagnetism), but also some new effects by the coupling of single ferroics which greatly widened the scope of application of ferroics material. Ferromagnetic-ferroelectric composite material is one of the categories and the most typical representation of such multiferroic materials which not only possess ferroelectricity and ferromagnetism, but also produce a special magnetoelectric effect.In this paper, we select the typical multiferroic material BiFeO3which is studied quite maturly not only in the theory but also in the experiments and the NiZnCu ferrites which is applied widely, and make the compound material by them as our main object of study. The results are as follows:(1) We study the influence of Iron deficiency of Low Temperature Sintered NiZnCu ferrites on the dielectrical and magnetic properties of the compound material. NiZnCu ferrites was produced by sol-gel method and their chemical formula are Nio.2Zno.2Cuo.6Fe2-xO4-3/2x(x=0,0.02,0.06,0.08,0.1). Then they were compounded by BiFeO3in ratio of5:5and by comparing their magnetic and electric properties, we find the component is Nio.2Zno.2Cuo.6Fe190O3.85, its dielectrical and magnetic properties are better.(2) We study the influence of the sintering temperature on the microstructure and magnetelectric properties of the compound materials. XRD and SEM spectra showed that with the development of sintering temperature two phases coexist of composites have relatively dense structure with finer crystallites, when the sintering temperature is730℃, a great deal of BiFeO3decompose the Bi25FeO39and Bi2Fe4O9. The existence of Bi25FeO39and Bi2Fe4O9lead to grain growth abnormally and decrease the densification and the dielectric and magnetic properties, when the sintering temperature is700℃the dielectric and magnetic properties are better.(3) We study the the different compound ratio on the microstructure of the compound materials and on their magnetelectric properties. BiFeO3which has ferroelectric and weakly magnetic properties was compounded by the chosen NiZnCu ferrite which has ferromagnetic property in ratio of xBiFeO3-(1-x)NiZnCu(x=0.1,0.3,0.5,0.7,0.9). XRD and SEM spectra show that composites have coexisted two phases, the minority of BiFeO3have decomposed, but didn’t have chemical reaction. Electric and magnetic measurements results have showed composites have magnetic hysteresis loop and P-E loop, which indicated magnetic order of ferrite maintain well in composites. When x=0.5the saturate magnetization is160emμ/g and coercivity value is64G. However, well saturated polarization hysteresis loops have not been obtained because of low electrical resistivity.(4) Also, we study the influence of the different synthetic process on the compound material. BiFeO3was compounded by the NiZnCu which was produced by hydrothermal method and by the NiZnCu which was produced by sol-gel method respectively, and we find that the compound material by the first method have higher density and better dielectric and magnetic properties. |
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