Fe/Al_2O_3纳米复合材料的结构和磁性

Structure and magnetic properties of Fe/Al_2O_3 nanocomposites

采用溶胶-凝胶法制备了复合材料Fe2O3/Al2O3,将其在氢气中还原得到了纳米复合材料Fe/Al2O3。利用X-ray衍射、Mssbauer效应和振动样品磁强计对样品的结构和性质进行了研究,结果表明,Fe2O3含量对样品的还原过程及结构和性质有明显的影响。随Fe2O3含量的增加,还原后样品中α-Fe的晶粒尺寸变大,样品的比饱和磁化强度增加,矫顽力减小。Mssbauer效应结果显示,在一些样品中存在超顺磁现象和FeAl2O4相。

The Al2O3/Fe2O3 composite powder was prepared by the sol-gel technique, and the prepared powder was reduced in the H2 atmosphere to obtain the Fe/Al2O3 nano-composite. The structure and the properties of the samples were investigated through the X-ray diffraction, Moessbauer spectroscopy and the vibrating sample magnetometer. The results showed that the Fe2O3 content has significant effects on both the reducing process and the structure and properties of the samples. With the increasing of Fe2O3 content, the α-Fe grains in the samples after reduction grow, the specific saturated magnetization goes up, and the coercivity decreases. The superparamagnetism and the FeAl2O4 phase may be observed through M6ssbauer spectrometry.