非磁性微球掺杂对纳米磁流体场诱导双折射特性的影响

Influence of Nonmagnetic Microsphere Doping on Magnetic-field-induced Birefringence of Nanostructured Magnetic Fluids

利用二氧化硅和聚苯乙烯非磁性微球掺入铁氧体纯磁流体中,制得了复合磁流体.定性地研究了复合磁流体在外磁场作用下的双折射与非磁性微球的种类、掺杂浓度以及纯磁流体自身浓度的关系.研究表明,不同浓度的纯磁流体掺杂等量的聚苯乙烯微球对其双折射随磁场的变化趋势影响不同;同一浓度的纯磁流体掺杂不同种类的非磁性微球,对其双折射的影响也不同;掺杂等量但不同比例的两种非磁性混合微球所形成的复合磁流体中,其中一种非磁性微球对其双折射的影响起主导作用,使得该复合磁流体双折射随磁场的变化趋势与起主导作用的非磁性微球单独掺杂时相似.

Composite magnetic fluids were obtained by doping silicon dioxide and polystyrene nonmagnetic microspheres into the pure ferrite magnetic fluids.The relationship between the magnetic-field-induced birefringence of composite magnetic fluids and the species,concentrations of nonmagnetic microspheres and pure ferrite magnetic fluids were investigated qualitatively.The results indicate that pure magnetic fluids with different concentrations doped with equal quantity of polystyrene microspheres have different variation trends for the birefringence with respect to the externally magnetic field.Different kinds of nonmagnetic microspheres have different influences on the change of birefringence after doping into the same pure magnetic fluids.When doping with two-kind-mixed nonmagnetic microspheres（equal quantity but different proportion between the two kinds of microspheres）,one kind of the nonmagnetic microspheres will play a leading role in the variation of birefringence with externally magnetic field.Then,the variation trend of the birefringence with externally magnetic field for the as-prepared composite magnetic fluids is similar to that only doped with the leading nonmagnetic microspheres.