Structural transitions in thermotropic ferronematics

Abstract

The structural instabilities in ferronematics based on different types of liquid crystals, exposed to electric or magnetic fields oriented perpendicular (Fredericksz transition) and parallel to the initial director, were studied within the Burylov and Raikher’s theory. Using the capacitance measurements the critical electric (magnetic) fields <i style="">E_FN</i> (<i style="">B_FN)</i>, corresponding to the Fredericksz transition, and fields <i style="">E_max</i>, (<i style="">B_max</i>,), at which the initial perpendicularity between director <i style="">n^→ </i> and magnetic moment <i> m^→ </i> breaks-down in field parallel to the initial director, were found. These values were then used for the estimation of the surface density of the anchoring energy <i style="">W</i> of liquid crystal molecules on the magnetic particle surface.