Flexoelectric polarization in nematic liquid crystals measured by field on-off pyroelectric technique
Blinov L.M., Ozaki M., Yoshino K.
PACS: 64.70.Md, 77.70.+a, 77.84.Nh
A novel, pyroelectric effect based technique was developed for the direct measurements of flexoelectric polarization in hybrid aligned nematic cells. The pyroelectric response is measured, first, in the field off regime, and then with the bias field applied. The latter allows a direct comparison of Pf with the field induced polarization over the whole range of the nematic phase of a standard compound 5CB. The sum of the flexoelectric coefficients (ei +إع) was shown to be negative and its dependence on the nematic order parameter does not follow a simple law (linear or quadratic) as was predicted theoretically. Dynamics of P^ is discussed in terms of the order parameter fluctuations.