压力对纳米CoFe2O4/SiO2复合材料结构的影响

摘要

采用溶胶-凝胶工艺和高温高压实验技术,制备了纳米CoFe2O4/SiO2复合材料.利用X射线衍射仪、扫描电子显微镜和振动样品磁强计,对样品的结构、微观形貌和磁性进行了研究,并对CoFe2O7中阳离子的占位情况进行了讨论.结果表明,随着处理压力的升高,样品的晶粒尺寸增大,品格常数减小,比饱和磁化强度增大.通过计算结果可以推断,压力的升高导致CoFe2O4中的部分Fe3+从A位移向了B位,而部分Co2+则从B位移向了A位.%Combined with sol-gel technology and high-pressure and high-temperature technique, CoFe2O4/SiO2 nanocomposites are fabricated. The structure and magnetic property of the nanocomposites are monitored by X-ray diffraction ( XRD) , scanning electron microscope (SEM) and vibrating sample magnetometer (VSM). The results show that the lattice constant of CoFe2O4 decreases but the grain size increases with increasing treatment pressure in the experiment. Moreover, the specific saturation magnetization increases gradually with increasing treatment pressure. According to the calculation results,it can be concluded that the increasing pressure leads to the Fe3+ ions transfer from A sites to B sites and the Co2+ ions transfer from B sites to A sites.