掺Dy^(3+)铁氧体纳米磁颗粒尺寸与磁学特性的相关性

Study on the Correlation Between Size and Magnetic Properties of Dy^(3+)-doped Ferrite Magnetic Nanoparticles

在水相体系中用化学法制备出不同尺寸的掺Dy3+铁氧体纳米磁颗粒。采用透射电子显微镜(TEM)、X射线衍射仪(XRD)、超导量子干涉仪(SQUID)表征了样品的形貌、结构、室温磁学性能。TEM图片表明,样品的形貌近似球形,平均粒径在15～24nm之间;XRD图谱表明,磁颗粒的物相以Fe3O4为主,结构为面心立方尖晶石型;SQUID测试结果表明,磁颗粒的尺寸不同则磁学特性有所不同,呈现出饱和磁化强度(Ms)随粒径增大而升高的规律;粒径小则剩余磁化强度(Mr)、矫顽力(Hc)小,粒径增大则剩余磁化强度、矫顽力升高。

Dy^3＋-doped ferrite magnetic particles with different size were prepared with chemical method in the water phase system. The morphology, crystal structure and magnetic properties of the samples at room temperature were characterized by TEM, XRD, and super-conducting quantum magnetometer device （SQUID）. TEM photographs showed that the average particle size of the sample is from 15 nm to 24 nm, the morphology is spherical. XRD pat- terns showed that the magnetic particles＇ phase is given priority to Fea 04, crystal type is face-centered cubic spinel structure. SQUID test results showed that different particle sizes have different magnetic properties, saturation magnetization （Ms） improve along with the increase of the particle size, and small particle sizes have small Mr and He, which improve with the increase of particle size.