CoFe_2O_4纳米颗粒的制备及其磁学性能

Synthesis and Magnetic Properties of CoFe_2O_4 Nanoparticles

采用溶胶凝胶法制备了CoFe2O4纳米颗粒,分别使用聚乙烯醇(PVA)和聚乙二醇(PEG)作为分散、凝胶剂,用X射线衍射仪(XRD)、扫描电子显微镜(SEM)和综合物性测量系统(PPMS)对CoFe2O4纳米颗粒的结构组成及物相、形貌尺寸和磁学性能进行分析研究。对比了两种分散剂制备的CoFe2O4纳米颗粒的磁学性能,并研究了不同量的PEG对CoFe2O4纳米颗粒的磁学性能的影响。结果表明:用PEG制得的CoFe2O4纳米颗粒的饱和磁化强度(143.11emu/g)比用PVA制备的CoFe2O4纳米颗粒的饱和磁化强度(62.81emu/g)大很多,其主要原因是Co2+在A位和B位的重新分布;PEG用量不同时,得到的CoFe2O4纳米颗粒尺寸不同,而颗粒尺寸大小又是影响CoFe2O4纳米颗粒的饱和磁化强度的主要因素;用4gPEG制备的CoFe2O4纳米颗粒的形貌、尺寸和磁学性能最好。

CoFe2O4 nanoparticals were synthesized by sol-gel method,using polyvinyl alcohol（ PVA） and polyethylene glycol（ PEG） as dispersants and gelatas,respectively. The morphology,size and magnetic properties of the nanoparticals were analyzed by X-ray diffraction（ XRD）,scanning electron microscope（ SEM）,physical property measurement system（ PPMS）,respectively. The magnetic properties of the nanoparticals prepared using PVA was compared with that prepared using PEG,meanwhile the influence of different dosages of PEG on the magnetic properties of Co Fe2O4 nanoparticals was investigated as well.The results indicate that the saturation magnetization of the nanoparticals prepared using PEG（ 143. 11 emu / g） is much larger than that of the nanoparticals prepared using PVA（ 62. 81 emu / g）,which is mostly due to the redistribution of Co2 ＋in A site and B site. The size of CoFe2O4 nanoparticles is one of important factors determining the saturation magnetism of Co Fe2O4 nanoparticles,which is different when the amount of the PEG is different. In summary,the morphology,size and the magnetic properties of Co Fe2O4 nanoparticles are all optimized when prepared using 4 g PEG.