Freedericksz transition in smectic-A liquid crystals doped by ferroelectric nanoparticles

The structure, orientation and physical properties of liquid crystals is significantly affected by doping of ferroic (ferromagnetic and ferroelectric) nanoparticles into liquid crystals. Behavior of these suspensions in external fields depends on anchoring energy, volume fraction of doped nanoparticles, and sign of dielectric anisotropy of liquid crystals as well as relative orientation of director and local polarization of nanoparticles. Here, the threshold voltage for molecular reorientation (Freedericksz transition) is estimated theoretically in smectic-A liquid crystals doped by spherical ferroelectric nanoparticles, near the smectic-A to smectic-C transition temperature taking into account local electric field effects. It is shown that the threshold voltage is decreased by doping ferroelectric nanoparticles into liquid crystals.