Measurement of Birefringence and Dichroism in Magnetic Fluids Doped with Nonmagnetic Polystyrene Microsphere

Abstract

In this study, we used the developed Stokes polarimeter for concurrent measurement of the magnetic-field-induced linear birefringence and dichroism in composite magnetic fluids (CMFs). CMFs were obtained by doping nonmagnetic microspheres into pure ferriferous oxide (Fe3O4) MFs. Experimental results show pure Fe3O4 MFs of different volume particle concentrations and CMFs doped with polystyrene (PS) microspheres of equal quantity have similar variation trends for the retardance and dichroism under externally magnetic field. The relation between the linear birefringence and dichroism of CMFs doped with PS microspheres of different concentrations and those of pure Fe3O4 MF were investigated. It is found that the suppression of both retardance and dichroism increases with the increasing concentrations of PS microspheres in CMFs. One of double doped microspheres as PS in CMFs plays a dominate role than the other microsphere as silica for the suppression of both retardance and dichroism.