Lowering of the Magnetic Fréedericksz transition threshold in nematic liquid crystals doped with ferromagnetic nanoparticles

We show that magnetic colloids could increase the coupling of a liquid crystal to a week magnetic field. Magnetic Fréedericksz transition in a planarly oriented nematic liquid crystal doped with spherical ferromagnetic nanoparticles is considered theoretically. It is shown that even spherical nanoparticles could decrease a threshold of this transition because they strongly increase the magnetic field in the medium. This phenomenon indicates the possibility to use the considered system in magneto-optical displays.