掺Dy^(3+)铁氧体硅油基磁流体磁特性与温度的相关性研究

Correlation Between Temperature and Magnetic Properties of Dy^(3+)-doped Ferrite Silicon-oil-based Magnetic Fluid

利用液相共沉淀法制备了纳米掺Dy3+铁氧体磁颗粒,用表面活性剂修饰后,在超声振荡下分散在硅油中制得磁流体。分别用TEM、XRF、XRD、SQUID分析手段对样品进行了表征,在203~358 K范围内,研究了温度变化对磁流体磁特性和粘度的影响。结果表明:制备的磁颗粒平均粒径约16.3 nm、物相主要是Fe2O3、Dy2O3,结构为面心立方尖晶石型。通过磁性能测试发现,磁流体的饱和磁化强度(MS)、矫顽力(HC)和粘度随温度(T)的降低,呈现出增大的变化规律;并且还发现,298 K≤T≤358 K时,温度降低对矫顽力和粘度的影响较小;T<298 K时,温度降低,矫顽力和粘度明显增大。

Dy3. -doped ferrite magnetic nano-particles were prepared by the liquid phase co-precipitation method, then modified by surfactant, the magnetic particles were dispersed in silicon-oil under the ultrasonic vibration to obtain the silicon-oil-based magnetic fluid. The samples were characterized by TEM, XRF）, XRD and SQUID. The effects of various temperatures on magnetic properties and viscosity of magnetic fluid were investigated in the range of 203 - 358 K. The results indicate that the phase compositions were mainly Fe203, Dy：O3 with face-centered cubic spinel when the average diameter of magnetic particles is ca. 16. 3 nm. Though the super-conducting quantum magnetometer test, the saturation magnetization （ Ms ）, the regular changes of the coercitivity （ Hc ） and viscosity of the magnetic fluid increase with the decrease of temperature. The coercitivity and viscosity changes a little with the decrease of temperature in the range of 298 K and 358 K. While the temperature is lower than 298 K, the coercitivity and viscosity were improved remarkably with the decrease of temperature.