Anomalous transport of magnetic colloids in a liquid crystal-magnetic colloid mixture

Abstract: We report an extensive molecular dynamics study on the translational dynamics of a hybrid system composed of dipolar soft spheres (DSS), representing ferromagnetic particles, suspended in a liquid crystal (LC) matrix. We observe that the LC matrix strongly modifies the dynamics of the DSS. In the isotropic regime, the DSS show a crossover from subdiffusive to normal diffusive behavior at long times, with an increase of the subdiffusive regime as the dipolar coupling strength is increased. In the nematic regime, the LC matrix, due to collective reorientation of LC particles, imposes a cylindrical confinement on the DSS chains. This leads to a diffusive dynamics of DSS along the nematic director and a subdiffusive dynamics (with an exponent $\sim 0.5$) in the perpendicular direction. The confinement provided by the LC matrix is also reflected by oscillatory behavior of the components of the velocity autocorrelation function of the DSS in the nematic phase.