Electric-field-induced isotropic-nematic phase transition

We measure optically the quadrupolar order S induced by a stabilizing electric field E in the isotropic phase of the nematogenic 4'-n-pentyl-4-cyanobiphenyl, with large positive dielectric anisotropy εₐ{~}10. For high enough field and low enough temperature, a paranematic-nematic first-order transition is induced, with a critical point at Ec=1.41×{}10⁵ V/cm, Tc=TNI+0.65 K, and Sc=0.15, where TNI is the nematic-isotropic phase-transition temperature.