### Abstract

In homeotropically aligned nematics with negative dielectric anisotropy the electrohydrodynamic instability occurs above a bend Fréedericksz transition. In the presence of a magnetic field H→ parallel to the liquid crystal slab, ordered roll patterns with a welldefined uniform wave vector k→_{id} appear above the onset of convection. By rotating the cell around an axis perpendicular to the slab by a small angle α, one can manipulate the system into a state with wave vector k→ = k→_{id} + Δk→, where Δk→ is roughly perpendicular to k→_{id}. We have studied experimentally the motion of defects, which then move essentially perpendicular to the rolls. The direction as well as the magnitude of the velocity as a function of Δk→ agrees with predictions of the weakly nonlinear theory. In particular, we obtain evidence for the nonanalyticity for Δk→ → 0.

Original language | English |
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Pages (from-to) | 824-830 |

Number of pages | 7 |

Journal | Europhysics Letters |

Volume | 57 |

Issue number | 6 |

DOIs | |

Publication status | Published - Aug 19 2002 |

### ASJC Scopus subject areas

- Physics and Astronomy(all)

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## Cite this

*Europhysics Letters*,

*57*(6), 824-830. https://doi.org/10.1209/epl/i2002-00585-0