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An electro-magneto-optical resonance method for determination of the value and sign of the flexoelectric coefficients in nematics

H. P. HINOV1,* , Y. MARINOV2

Affiliation

  1. Institute of Solid State Physics, Bulgarian Academy of Sciences, 72 Tzarigradsko Chaussee Blvd., 1784 Sofia, Bulgaria
  2. Liquid Crystal Laboratory, bBiomolecular Layers Laboratory

Abstract

A novel method for determining of the flexoelectric coefficients of nematics has been proposed. It is based on the electro-optical behaviour of the surface-induced flexoelectric domains in an additional applied magnetic field in the Z direction. The electro-magneto-optical curves have a resonance character due to competition between the flexoelectric, dielectric and magnetic torques. From the resonance, where the intensity of the transmitted light is maximal, one can obtain formulae which permit calculation of a relation between the flexoelectric coefficients of bend e3x, splay e1z, and the values of the electric and magnetic fields. As a second relation, we choose the sum of the two flexoelectric coefficients. The obtained quadratic equations have been solved numerically with the aid of computer, for all permitted negative and positive values of the sum of the two coefficients. Finally, the values of the coefficients of bend and splay are discussed. Their variations for small values of the total flexoelectric coefficient around zero are the most interesting..

Keywords

Surface-induced flexoelectric domains, Electric and magnetic fields, Electro-magneto-optical resonance, Flexoelectric coefficients of nematics.

Submitted at: Nov. 1, 2006
Accepted at: Feb. 15, 2007

Citation

H. P. HINOV, Y. MARINOV, An electro-magneto-optical resonance method for determination of the value and sign of the flexoelectric coefficients in nematics, Journal of Optoelectronics and Advanced Materials Vol. 9, Iss. 2, pp. 435-437 (2007)