Stripe patterns in the magnetic reorientation of a glass-forming nematic liquid crystal |
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Authors: | M?Grigutsch Email author" target="_blank">R?StannariusEmail author |
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Institution: | 1.Universit?t Leipzig, Institut für Experimentelle Physik I,Leipzig,Germany |
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Abstract: | We study spontaneous pattern formation in a glass-forming nematic liquid crystal during the magnetically induced dynamic Fréedericksz
transition. Pattern growth rates and wavelengths as functions of the magnetic field are extracted from optical transmission
textures of thin planar cells. The characteristics of the observed stripe pattern can be related to viscoelastic parameters
of the nematic by means of a linear stability analysis of director fluctuation modes. The viscous properties of the material
allow to vary the time scales of the experiment with temperature by orders of magnitude, leaving the spatial structure of
the pattern essentially unchanged. We find that the ratios of shear and rotational viscosity coefficients relevant for the
pattern wavelength selection remain constant in the temperature range investigated, whereas their absolute values change by
almost two orders.
Received 23 November 2001 and Received in final form 19 April 2002 |
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Keywords: | PACS 61 30 Eb Experimental determinations of smectic nematic cholesteric and other structures – 47 20 -k Hydrodynamic stability |
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