【摘要】 采用湿化学法制备出稀土Dy3+掺杂的纳米Fe3O4磁粒子,用月桂酸进行了表面修饰,研究了磁粒子在室温和深冷(200.2~56.5 K)状态下的磁性能。经X射线衍射分析发现,适量的Dy3+掺杂不会改变纳米Fe3O4磁粒子的晶型结构。透射电镜(TEM)照片表明,制备出的纳米磁粒子成球性好,且大部分磁粒子的粒径在14 nm左右。通过磁性测量仪、振动样品磁强计(VSM)对磁性能进行了表征。磁化曲线表明掺杂引起磁性能发生变化,磁粒子室温下无剩磁和矫顽力,具有超顺磁性;深冷状态下出现剩磁和矫顽力,且随温度的降低,剩磁和矫顽力增大,不具有超顺磁性,饱和磁化强度略高于室温值。更多还原

【Abstract】 The Dy3+-doped Fe3O4 magnetic nanoparticles were prepared by wet chemical method,and lauric acid was used to modify the surface of magnetic nanoparticles.The magnetic properties in room temperature and cryogenic temperature(200.2~56.5 K) were investigated.According to XRD analysis,the crystal structure of Fe3O4 magnetic nanoparticles doped with appropriate amount Dy3+ was not changed.The TEM showed that the size of the prepared product was about 14 nm.The magnetic propertied were characterized by magnetism measuring instrument and VSM.The magnetization curve indicated that the Dy3+-doping resulted in the changes of magnetic property.The magnetic particles have superparamagnetism and have not remanent magnetization(Mr) and coercivity(Hc) at room temperature.The remanent magnetization and coercivity were appeared at cryogenic temperature,and they would get stronger with decreasing of the temperature,which have not superparamagnetism.The saturation magnetization in cryogenic temperature was slightly stronger than in room temperature.更多还原