掺硅对γ-Fe_2O_3微粒的结构和磁性能的影响

Influence of Silicon Doping on the Structure and the Magnetic Property of γ- Fe_2O_3 Particle

本文采用掺硅制得了小尺寸的含硅γ—Fe_2O_3微粒.基于Furuhashi方法对不同硅含量的掺硅γ—Fe_2O_3微粒进行了X射线衍射结构研究.结果表明,随着硅含量增加,晶胞参数逐渐减小,表明形成掺硅γ—Fe_2O_3固溶体.掺入的Si^(4+)阳离子有很强的占据类尖晶石结构中四面体位的趋势,对氧参数及四面体位和八面体位的平均间隙大小也有一定影响.本文还利用Stokes和Wilson公式计算了掺硅对晶粒大小和晶格畸变的影响.发现随着掺硅量增大,晶粒尺寸明显减小,晶格畸变变化不大.最后对掺硅γ—Fe_2O_3磁粉的矫顽力和比饱和磁化强度作了详细的分析和讨论.

The structure of Si - doped γ - Fe2O3 small particles prepared by doping with different silicon content has been investigated by X - ray diffraction based on Furuhashi method. The results show that the lattice parameters decrease continuously with increasing silicon content,which suggests an evidence of a solid solution for Si - doped γ - Fe2O3. The Si4+ cation in the like - spinels appears a strong tendency to distribution in the tetrahedral site. The oxygen parameter as well as the mean size of interstices of tetrahedral and octahedral also appears a certain influence of silicon doping. Additionally, grain sizes and lattice distortions of the samples which were calculated following the Stokes and Wilson formula indicate a significant decrease for the grain size with increasing silicon content and a little change for the lattice distortion. Finally, the coercivity and saturation magnetization of the Si- doped r-Fe2O3 particles are discussed.