THERMAL-CONVECTION IN A PLANAR NEMATIC LIQUID-CRYSTAL WITH A STABILIZING MAGNETIC-FIELD

We report experimental results for thermal convection in a horizontal layer of a planar nematic liquid crystal [4-n-pentyl-4'-cyanobiphenyl (5CB)] heated from below in a uniform horizontal magnetic field H. The threshold for convection and the critical wave-vector components were measured as a function of H. The convection rolls were oriented with their axes normal (oblique) to the field direction for H < H(L1) (H(L1) < H < H(L2)), where H(L1) and H(L2) are the lower and upper Lifshitz fields, respectively. Above H(L2) the orientation was parallel to H. The dependence of the orientation on H near H(L1) and H(L2) agrees with theoretical predictions.