The effect of external applied fields on the third order nonlinear susceptibility of ferro-nematics

This experimental work reports measurement of the third order nonlinear susceptibility of the nematic liquid crystals with the impurity of Fe3O4 nanoparticles with the mean diameter of 34 nm and weight concentration of 1 wt.%. The study was performed without and under the influence of electric and magnetic field consequently by applying different voltages and induction 0.5 T. The results show in the case of nematic liquid crystals with magnetic nanoparticles, the parameter changes caused by the external fields depend on the direction of external fields with respect to the director axis n→ and then the type of initial alignment. The direction of applied external fields is perpendicular to the cell surface, so there was no observable shift in the nonlinearity in the case of homeotropic alignment sample. The experimental results show that the change in the third order nonlinear behavior of homogeneous-aligned cells reoriented the ferro-nematic molecules to their homeotropic state.