The anchoring energy of liquid crystal molecules to magnetic particles in HAB-based ferronematics

Abstract

In this work we describe the magnetic Freedericksz transition in HAB-based (4,4′-di-n-heptylazoxybenzene) ferronematics. The ferronematic samples were prepared with two different volume concentrations of magnetic particles φ1 = 2 × 10-5 and φ2 = 2 × 10-4. The liquid crystal HAB is nematic at the temperatures from ≈ 53°C to 70°C and smectic A at the temperatures under 53°C The anisotropy of dielectric permitivity of HAB liquid crystal is positive in nematic phase and negative in smectic A phase. The magnetic Fredericksz transition was studied in nematic phase at temperature 60°C.