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采用改进的化学共沉法成功制备了CoFe2O4铁氧体纳米颗粒.X射线衍射谱表明样品具有单相的尖晶石结构,空间群为Fd3m-O7h;扫描电镜结果表明CoFe2O4纳米颗粒呈规则的球形,粒径尺寸主要分布在20-30nm之间;样品热磁曲线异常的不可逆行为被发现,并且升温测量过程中样品的居里温度稍高于重复测量的居里温度,可以解释为在磁性能测量过程中升降温改变了Co2+在四面体位和八面体位之间的分布;CoFe2O4纳米颗粒样品的矫顽力低于理论值,这归因于我们合成的CoFe2O4纳米颗粒处于单畴结构状态和从亚铁磁到超顺磁的转变态.
The CoFe2O4 ferrite nanoparticles were successfully prepared by the improved chemical coprecipitation method. The X-ray diffraction spectra showed that the sample had a single-phase spinel structure with a space group of Fd3m-O7h. The scanning electron microscopy showed that the CoFe2O4 nanoparticles were spherical , The size of the particles are mainly distributed in the range of 20-30nm; the irreversible behavior of the sample is found, and the Curie temperature of the sample is slightly higher than the Curie temperature of the repeated measurement during the temperature rising measurement, The temperature rising and cooling during the measurement changed the distribution of Co2 + between tetrahedral sites and octahedral sites. The coercivity of CoFe2O4nanoparticles samples was lower than the theoretical value, which was attributed to the monodomain structure of CoFe2O4nanoparticles and Ferromagnetic to superparamagnetic transitional state.