The Structural Phase Transitions in 6CB-Based Ferronematics

The structural transitions in ferronematics based on the thermotropic nematic liquid crystal 4-cyano-4'-hexylbiphenyl were studied. The ferronematic samples were prepared by doping with magnetic suspension consisting of $Fe_3O_4$ particles (10 nm in diameter) coated with oleic acid as a surfactant with different volume concentrations of magnetic particles (from $10^{-5}$ to $10^{-3}$). Freedericksz transitions were studied in combined electric and magnetic fields. The experimental results indicated soft anchoring with perpendicular initial orientation between the magnetic moment of the magnetic particles and director.