SiO2基底中MnFe2O4纳米晶的制备与表征

Preparation and characterization of MnFe_2O_4 nanocrystalline dispersed in a silica matrix

在N,N-二甲基甲酰胺(DMF)存在下,以溶胶-凝胶技术成功地制备了无定形二氧化硅基底中均匀分布的MnFe2O4纳米晶。由粉末X射线衍射和电子衍射确证了MnFe2O4纯相的生成。由粉末X射线衍射和红外吸收光谱研究了MnFe2O4纳米晶形成过程。尖晶石结构的MnFe2O4在800℃时开始形成,900℃时基本完成。磁性质测量表明在烧结到900℃的样品中,MnFe2O4纳米晶室温具有超顺磁性,78K时为软磁性。1000℃和1100℃下得到的样品室温和78K时都具有软磁性。

Uniformly dispersed MnFe2 04 nanocrystals were successfully synthesized in an amorphous silica matrix by the sol-gel method in the presence of N, N-dimethylformamide （DMF）. The formation of pure MnFe2O4 was confirmed by powder X-ray diffraction （XRD）and electron diffraction. The structural development of MnFe2O4 nanocrystals was followed by powder X-ray diffraction and IR absorption spectroscopy. The formation of spinel structure of MnFe2O4 started at 800℃, and completed at 900℃. Field-dependent magnetization measurements at room temperature indicated superparamagnetic nature of MnFe2O4 nanocrystals in N-900. N-900 at 78K and N-1000 and N-1100 both at room temperature and 78K exhibited soft magnetic behavior.