Influence of pressure on the electric-field-induced phase transitions in liquid crystals
Department of Physics, Banaras Hindu University, 221005, Varanasi, India
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Accepted: 27 March 2006
Published online: 8 May 2006
Within the framework of Landau-de-Gennes formulation, we analyse the effect of pressure on electric-field-induced phase transitions in a liquid crystal which shows spontaneously an isotropic-smectic A transition. Inferring from the experimental pressure dependences on the layer spacing in smectic A phase, as well as the nematic-smectic A metastable temperature T * AN, we incorporated the pressure dependence in the free energy through (the surface energy term) and the coupling between the quadrupolar nematic ordering Qij and the smectic order parameter ψ. From the S-T phase diagram, we found that the stability of field-induced nematic phase increases with pressure, whereas the discontinuity of the transition decreases. Also, the region where paranematic phase transits directly to smectic A phase increases with pressure.
PACS: 05.70.Fh Phase transitions: general studies – / 64.70.Md Transitions in liquid crystals – / 61.30.-v Liquid crystals –
© EDP Sciences, Società Italiana di Fisica and Springer-Verlag, 2006