自燃烧法制备CoFe_2O_4纳米颗粒及其磁性研究

Synthesis and Magnetic Propertise of CoFe_2O_4 Nanoparticles by Auto-Combustion Method

用柠檬酸自燃烧法制备出CoFe_2O_4纳米粉末,对燃烧产物在不同温度下热处理,用扫描电镜(SEM),x射线光电子能谱(XPS),红外吸收谱(IR)对燃烧产物进行形貌,成分以及化学键分析,用x射线衍射(XRD)对燃烧产物及热处理产物进行晶体结构分析,结果显示燃烧产物为CoFe_2O_4纯相,尺寸在40～80nm之间,且有较高的分散性和低的团聚。用振动样品测磁计(VSM)在室温下测量了燃烧产物及热处理产物的磁滞回线,发现测得的比饱和磁化强度(Ms),矫顽力(Hc)以及剩磁比(Mr/Ms)均强烈依赖于热处理温度,Ms随热处理温度升高而增大,而样品的Hc与Mr/Ms均当热处理温度为400℃时达到最大,并且Hc达到了3180Oe。

CoFe2O4 nanoparticles were prepared by citric acid auto-combustion method, the as-burnt powders were calcined at different temperature, the morphology, component, and chemical bond were respectively studied by Scanning Electron Microscopy （SEM）, x -ray Photoelectron Spectroscopy （XPS）, and Infrared spectroscopy （IR）, the crystal structure of the as-burnt powders and products calcined at different temperature was characterized by X-Ray Diffraction （XRD）, the results shows that the as-burnt powders were pure CoFe2O4 phase with high dispersibility and relatively low agglomeration, and the particle size is between 40 and 80nm, The magnetic hysteresis loops of the as-burnt powders and products calcined at different temperature were collected at room temperature （RT） using a vibrating sample magnetometer （VSM）, the results shows that saturation magnetization （Ms）, coercivity （Hc） and remanence ratio （Mr/Ms） were drastically depending upon the annealing temperature, Ms increased with increasing temperature, while Hc and Mr/Ms both reached maximum values as the as-burnt powders were calcined at 400℃, and Hc reached 31800e.