Nematics under external fields: static stability analysis

The stability of the (bulk) nematic director field under applied magnetic fields is studied using continuum theory. The stability analysis of two order parameter potentials allows the study of the influence of the external field on the development of static periodic distortions in the director field. The case of oblique applied fields is studied. In the frame of a phase transition analogy, where the angle of the field with respect to the unperturbed director plays the role of the external parameter, phase diagrams are shown for the critical angle for the director transition from the homogeneous to the distorted state, as a function of the Frank elastic anisotropy.