低温固相反应法制备CoFe_2O_4纳米颗粒

采用低温固相反应法以CoCl2、FeCl3和NaOH为原料制备了CoFe2O4铁氧体纳米粉体．采用X射线衍射仪（XRD）扫描电子显微镜（SEM）振动样品磁强计（VSM）对样品的成分、形貌和宏观磁性进行了表征，利用等加速穆斯堡尔谱仪对样品进行了穆斯堡尔谱的测量．结果表明，使用本方法可以在较低的温度下（90℃）方便地得到纯度较高，颗粒度（11～56nm）分布较均匀的CoFe2O4纳米颗粒．用这种方法制备的CoFe2O4粉体单畴临界尺寸在23nm左右．超精细场随着退火温度的升高而增大．

Solid State Synthesis of CoFe_2O_4 Nanoparticles at Low Heating Temperatures

CoFe2O4 ferrite nanoparticles were synthesized by a method of solid state synthesis at low tem- peratures using COCl2, FeCl3, NaOH as the materials. The structure, morphology, magnetic performance are characterized by a X-ray diffraction instrument （XRD）, a scanning electron microscope（SEM）as well as a vibrating sample magnetometer（VSM）. Mossbauer spectroscopy was used to analyse the samples. The results show that high purity of CoFe2O4 particles with the size distribution in the range from 11 to 56 nm can be obtained at low temperature （90℃）. The single domain critical size is about 23 nm . Mossbauer spectra indicate that the hyperfine field of the samples increases as the annealing temperature rises.