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The European Physical Journal E

, Volume 4, Issue 2, pp 183–192 | Cite as

Surface and flexoelectric polarization in a nematic liquid crystal 5CB

  • L.M. Blinov
  • M.I. Barnik
  • H. Ohoka
  • M. Ozaki
  • N.M. Shtykov
  • K. Yoshino

Abstract:

The temperature dependence of the surface polarization has been measured for both the planar and homeotropic orientation of a nematic liquid crystal at a solid substrate. A conventional liquid crystal 5CB, pure and doped with an azo-dye, was used in cells with controlled asymmetry for light absorption. The measurements have been made by a pyroelectric technique using short pulses of a YAG laser to create a temperature increment. The latter, in turn, was measured independently by a novel time-resolved “optical thermometer” technique monitoring temperature-dependent birefringence by a He- Ne laser beam. In accordance with the symmetry of the order parameter, the surface polarization has different sign for the two orientations, its magnitude ranges from -4 to +2pC/m. The same technique has been used for the measurement of the flexoelectric polarization in hybrid cells. The sum of the flexoelectric coefficients is e1 + e3 = - 13pC/m at 25°C.

PACS. 61.30.-v Liquid crystals – 77.70.+a Pyroelectric and electrocaloric effects – 77.84.Nh Liquids, emulsions, and suspensions; liquid crystals 

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Copyright information

© EDP Sciences, Springer-Verlag, Società Italiana di Fisica 2001

Authors and Affiliations

  • L.M. Blinov
    • 1
  • M.I. Barnik
    • 1
  • H. Ohoka
    • 2
  • M. Ozaki
    • 2
  • N.M. Shtykov
    • 1
  • K. Yoshino
    • 2
  1. 1.Institute of Crystallography, Russian Academy of Sciences, 117333, Leninsky prosp. 59, Moscow, RussiaRU
  2. 2.Department of Electronic Engineering, Graduate School of Engineering, Osaka University, 2-1 Yamada-Oka, Suita, Osaka 565-0871, JapanJP

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