First-order Fréedericksz transition at the threshold point for weak anchoring nematic liquid crystal cell under external electric and magnetic fields
Guan Rong-Hua (关荣华)ab, Yang Guo-Chen (杨国琛)b
a Department of Applied Physics, North China Electric Power University, Baoding 071003, China; b Institute of Material Physics, Hebei University of Technology, Tianjin 300130, China
Abstract Based on the modified formula of Rapini-Papoular, the equilibrium equation and boundary condition of the director have been obtained and the behaviour of the Fréedericksz transition at the threshold point has been studied for weak-anchoring nematic liquid crystal cells under external electric and magnetic fields with the methods of analytical derivation and numerical calculation. The results show that, except for the usual second-order transition, the first-order Fréedericksz transition can also be induced by a suitable surface anchoring technique for the liquid crystal cell given in the paper. The conditions for the existence of the first-order Fréedericksz transition are obtained. They are related to the material elastic coefficient $k_{11}$, $k_{33}$ the thickness of the liquid crystal cell, the external electric field and the strength of surface anchoring, etc.
Received: 20 June 2003
Revised: 18 August 2003
Accepted manuscript online:
Guan Rong-Hua (关荣华), Yang Guo-Chen (杨国琛) First-order Fréedericksz transition at the threshold point for weak anchoring nematic liquid crystal cell under external electric and magnetic fields 2003 Chinese Physics 12 1283
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