The Freedericksz Transition in a Spatially Varying Magnetic Field

Much is known about the Freedericksz transition induced by uniform electric and magnetic fields in nematic liquid crystals. In this work, we are interested effects of a spatially varying field on transition. Specifically, study director configuration homeotropic cell with cylindrical symmetry. The experiment conducted ring magnet which provides radial magnitude monotonically decreasing to zero at center. positioned central plane ring, normal parallel normal. Interference patterns between crossed polarizers were observed. modeled Frank–Oseen theory, computed interference pattern from simulated compared experiment. We conclude that if strength varies position cell, there no