一维Ni0.5Zn0.5Fe2O4/SiO2复合纳米结构的制备及其磁性能

采用溶胶-凝胶法结合静电纺丝技术制备了Ni_0.5Zn_0.5Fe₂O₄/SiO₂复合纳米纤维.利用热重-差热分析、X射线衍射、场发射扫描电镜、高分辨透射电镜和振动样品磁强计研究了前驱体纤维的热分解及相转化过程以及焙烧温度和SiO₂含量对目标纳米纤维的相组成、微观结构、形貌及磁性能的影响.结果表明,在450 ℃焙烧时,立方尖晶石结构已基本形成.随着焙烧温度由450 ℃升高到100

Preparation of one-dimensional Ni0.5 Zn0.5 Fe2O4/SiO2 composite nanostructures and their magnetic properties

The Ni_0.5Zn_0.5Fe₂O₄/SiO₂ composite nanofibers were prepared using sol-gel process combined with electrospinning. The thermal decomposition and phase inversion process of precursor nanofibers and the effects of calcination temperature and SiO₂ content on the phase composition, microstructure, morphology and magnetic property of the resulting nanofibers were studied by means of thermogravimetric and differential thermal analysis, X-ray diffraction, field emission scanning electron microscopy, high resolution transmission electron microscopy and vibrating sample magnetometer. The experimental results show that the cubic spinel structure is basically formed when the precursor nanofibers are calcined at 450 ℃ for 2 h. The average grain size of Ni_0.5Zn_0.5Fe₂O₄ contained in the composite nanofibers with 10 % SiO₂ and their specific saturation magnetization and coercivity increase with increasing calcination temperature. Amorphous SiO₂ additive can effectively restrain the growth of Ni_0.5Zn_0.5Fe₂O₄ nanocrystals. As a result, with SiO₂ content increasing from 0 to 20 % , the average grain size of Ni_0.5Zn_0.5Fe₂O₄ in the prepared Ni_0.5Zn_0.5Fe₂O₄/SiO₂ composite nanofibers calcined at 900 ℃ for 2 h decreases from 81.6 to 13.3 nm, and the specific saturation magnetization of these samples monotonically decreases, whereas the coercivity initially increases and then decreases due to the change of magnetic domain structure from multi-domain to single-domain along with the reduction in grain size. In addition, with the increase of SiO₂ content, the diameter of the as-prepared Ni_0.5Zn_0.5Fe₂O₄/SiO₂ composite nanofibers gradually increases and the surface becomes smooth.