Magnetic and Electric Field Induced Periodic Deformations in Nematics-Effect of Director Pretilt

Abstract

Using linear stability analysis, theoretical studies are reported on the formation of static periodic distortions (PD) in a nematic sample under the action of crossed electric (E) and magnetic (H) fields applied on a uniformly aligned initial director configuration (4). With the rigid anchoring hypothesis, results for director pretilt away from the homeotropic (40 # 0) reduce to those previously obtained for homeotropic alignment as a special case. Variation of magnetic tilt may lead to discontinuous change in the wavevector of PD. Increase of 4o quenches PD in favour of the aperiodic or homogeneous deformation (HD). Phase diagrams are presented for PD occurring in nematic materials with different types of susceptibility anisotropy.