用溶胶-凝胶方法制备了一种新型纳米复合永磁材料.XRD及SEM表明,由于这种材料的软磁相与硬磁相具有30nm左右尺寸而发生强烈的交换耦合作用,导致该种新材料具有优异的磁性能.%Permanent magnetic nsnocomposite FeSmO3/Fe2 O3 was prepared by sol-gel method and the influence of the heat treatment on magnetic properties and structure were study by X-ray diffraction (XRD), differential thermal analysis (DTA), scan electron microscopy (SEM), energy dispersive X-ray detector (EDX) and vibrating sample magnetometer (VSM). Experimental results show that it is necessary to preheat the gel at 400℃ for several hours. It can prevent growing of particles size and help to obtain ultrafine samples with a narrow size distribution at lower temperature. The microstructure of the two nanocomposite phases consists of hard magnet and soft magnet with an average size of 30nm when annealed by subsection at 600℃ for 1h in the end. These small particles allow effective exchange coupling between two phases and display enhancement of permanent magnetic properties comparing with pure FeSmO3. The magnetic properties are clearly size dependent. The sol-gel technique is more preferable for the preparation of nanocomposite because its process is easy, the experiment is simple and the product is stable.
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