Magneto-orientation response of ferronematic with a tilted orientation of the director and magnetization

Abstract

The article considers orientational transitions induced by a magnetic field in a highly dispersed suspension of ferromagnetic particles in a nematic liquid crystal – ferronematic. We research the case when, in the absence of an external magnetic field between the directions of the liquid crystal director and magnetization of the impurity particles, a constant pretilt angle is maintained, and the coupling of the liquid crystal molecules to the surface of the ferroparticles is assumed to be soft and planar. An example of such an impurity is ferromagnetic carbon nanotubes magnetized at a certain angle to their long axes. On the basis of the continuum theory, the equilibrium values of the orientation angles of the liquid crystal director and magnetization are calculated for different values of the pretilt angle. The results of calculations are compared with the previously considered case of planar coupling between the director and magnetization. Analytical expressions are obtained for determining the orientational and magnetic structure of the ferronematic in the case of weak magnetic fields. The magnetization of the ferronematic is studied for different values of the pretilt angle.