镝掺杂铁氧体纳米晶的制备、表征和磁性

Preparation,Characterization and Magnetic Properties of Ferrite Nanocrystals Doped with Dysprosium

采用化学共沉淀法制备出了镝掺杂铁氧体纳米晶,利用透射电子显微镜(TEM)、X射线衍射仪(XRD)、傅立叶红外光谱仪(FTIR)、古埃磁天平、振动样品磁强计(VSM)、X射线能谱仪(EDX)等仪器对产物进行了表征,研究了Dy3+掺杂量对铁氧体纳米晶的结构、磁性和粒度的影响.结果表明:适量稀土元素镝离子的掺杂可以提高尖晶石型铁氧体的磁性、降低矫顽力,当n(Fe3+)∶n(Dy3+)=14∶1时其磁性最强.Dy3+替代或充填进入了尖晶石晶格,且主要占据B位.掺杂了镝的铁氧体磁性纳米粒子粒度变小,且分布更集中、均匀,当Dy3+加入量为n(Fe3+)∶n(Dy3+)=14∶1时铁氧体纳米粒子的平均粒径由掺杂前的14nm降低到到8nm.这种具有超顺磁性的软磁铁氧体纳米晶可应用于纳米磁液领域.

Dy^3＋-doped ferrite nanocrystals were prepared by a chemical co-precipitation method and characterized by transmission electron microscopy （TEM）, X-ray diffraction （XRD）, Fourier transform infrared spectroscopy （FTIR）, Gouy magnetic balance, vibrating sample magnetometer （VSM）, and X-ray energy spectrum （EDX）, respectively. The effects of dysprosium contents on structure, magnetic properties and size of the ferrite were investigated. The results show that Dy^3＋can enhance the magnetic properties which are strongest while n（Fe^3＋） ： n（Dy^3＋） is 14 ： 1 among the samples prepared, and weaken the coercive force of the spinel ferrite. Dy^3＋ fills in the spinel ferrite lattice and mostly enters B site. The size of the Dy-doped ferrite nanoparticles becomes smaller and their distribution is more concentrated and uniform. The average diameter of the ferrite nanoparticles is 14 nm before doping and reduces to 8 nm after doping when n（Fe^3＋） ： n（Dy^3＋） is 14 ： 1. The results support the concept that the soft magnetic ferrite nanocrystals with superparamagnetism can be applied to nanometer magnetic fluid field.