title: Electroclinic effect in a chiral paranematic liquid-crystal layer above the bulk nematic-to-isotropic transition temperature.
abstract: Electroclinic measurements are reported for two chiral liquid crystals above their bulk chiral isotropic-nematic phase transition temperatures. It is found that an applied electric field E induces a rotation θ [∝Ε] of the director in the very thin paranematic layers that are induced by the cell's two planar-aligning substrates. The magnitude of the electroclinic coefficient dθ/dE close to the transition temperature is comparable to that of a bulk chiral nematic, as well as to that of a parasmectic region above a bulk isotropic-to-chiral smectic-A phase. However, dθ/dE in the paranematic layer varies much more slowly with temperature than in the parasmectic phase, and its relaxation time is slower by more than three orders of magnitude than that of the bulk chiral nematic electroclinic effect.
authors.affiliation: Department of Physics, Case Western Reserve University, Cleveland, Ohio 44106, USA.|CNRS UMR 7588, Université Pierre et Marie Curie, Institut des NanoSciences de Paris (INSP), 4 place Jussieu, 75005 Paris, France.|UPMC Université Paris VI, UMR 7588, Institut des NanoSciences de Paris (INSP), 4 place Jussieu, 75005 Paris, France.
authors.forename: Ian R
authors.initials: IR
authors.lastname: Nemitz
authors.affiliation: CNRS UMR 7588, Université Pierre et Marie Curie, Institut des NanoSciences de Paris (INSP), 4 place Jussieu, 75005 Paris, France.|UPMC Université Paris VI, UMR 7588, Institut des NanoSciences de Paris (INSP), 4 place Jussieu, 75005 Paris, France.
authors.forename: Emmanuelle
authors.initials: E
authors.lastname: Lacaze
authors.affiliation: Department of Physics, Case Western Reserve University, Cleveland, Ohio 44106, USA.
authors.forename: Charles
authors.initials: C
authors.lastname: Rosenblatt