不同磁场下水热制备CoFe_2O_4纳米颗粒及其磁性能的研究

Preparation and Magnetic Properties of CoFe_2O_4 Nanoparticles by Hydrothermal Method under Different Magnetic Fields

以Co(NO3)2·6H2O,Fe(NO3)3·9H2O,NaOH为原料,在不同外加磁场条件下进行水热处理,分别制备了颗粒尺寸为几纳米到20 nm的CoFe2O4纳米颗粒,通过XRD,TEM和振动样品磁强计对其晶体形貌和宏观磁性能进行表征。结果表明,采用水热法制备的CoFe2O4可获得纯度较高晶粒生长完整的CoFe2O4磁性纳米微粒,稳恒磁场条件对晶格常数,磁性能有较大的影响。当稳恒磁场在一定范围内时,随着稳恒磁场的增加,磁性颗粒的粒径增大,样品室温下的饱和磁化强度逐渐增大。但是当稳恒磁场超出一定范围时,随着稳恒磁场的减小,磁性颗粒的粒径减小,样品室温下的饱和磁化强度逐渐减小。

CoFe2O4 particles from several nanometers to 20 nm were prepared by hydrothermal method under different magnetic fields with Co（ NO3）2·6H2O,Fe（ NO3）3·9H2O,Na OH as raw materials. The crystal phase,morphology and macroscopic magnetic properties were characterized by XRD,TEM and vibrating sample magnetometer. The results show that CoFe2O4 powders with high purity are obtained after the hydrothermal reaction. Magnetic field has a great impact on the lattice constant and the magnetic properties. The particle size and the saturation of samples at room temperature decreases with the increase in magnetic flux density in certain magnetic range. But beyond the certain range,the particle size and the saturation increase of the magnetic flux density increasing.