Results 171 to 180 of about 388,640 (201)

Determination of piezoelectric and flexoelectric polarization in ferroelectric liquid crystals

Physical Review E, 2005
A method of determining the local polarization in chiral smectic liquid crystals is proposed. The method consists of simultaneous measurement of the electric permittivity and depth of electro-optic modulation in a helical liquid crystal using weak ac electric field.
W, Kuczyński, J, Hoffmann
openaire   +2 more sources

Surface Polarization and Flexoelectricity in Nematic Liquid Crystals

Molecular Crystals and Liquid Crystals Science and Technology. Section A. Molecular Crystals and Liquid Crystals, 1999
We propose a technique for the measurement of the surface electric polarization in nematic liquid crystals from the birefringence variations of the texture under weak vertical electric field.
Sandrine Forget, Ivan Dozov, Philippe Martinot-lagarde   +2 more
openaire   +1 more source

Large flexoelectric polarization in ceramic lead magnesium niobate

Applied Physics Letters, 2001
Flexoelectric coefficient μ12 is greatly enhanced in the relaxor ferroelectric lead magnesium niobate ceramic. Phenomenological analysis suggests the high dielectric permittivity is inadequate to explain the great enhancement. Temperature dependent measurement reveals a close relation between the flexoelectric polarization and the preexisting polar ...
Wenhui Ma, L. Eric Cross
openaire   +1 more source

Statistical theory of the flexoelectric polarization for the uniaxial nematic phase

Physical Review E, 2007
A statistical theory for the dipole flexoelectric (FE) polarization in liquid crystals is derived in the thermodynamic limit at small distortions and a small density. General microscopic expressions for the FE coefficients are rederived in the case of the uniaxial nematic phase.
openaire   +2 more sources

Nanoscale mechanical switching of ferroelectric polarization via flexoelectricity

Applied Physics Letters, 2015
Flexoelectric coefficient is a fourth-rank tensor arising from the coupling between strain gradient and electric polarization and thus exists in all crystals. It is generally ignored for macroscopic crystals due to its small magnitude. However, at the nanoscale, flexoelectric contributions may become significant and can potentially be utilized for ...
Yijia Gu, Zijian Hong, Jason Britson, Long-Qing Chen   +3 more
openaire   +1 more source

Flexoelectric effect and statistical properties in polar liquid crystals

Crystallography Reports, 2003
The structural properties and flexoelectric coefficients e 1 and e 3 of polar liquid crystals (LCs) such as 4-n-pentyl-4′-cyanobiphenyl (5CB) are studied in the nematic phase by the molecular-dynamics and statistical-mechanics methods. A number of order parameters, $$\bar P_{2L}
A. V. Zakharov, A. A. Vakulenko
openaire   +1 more source

Flexoelectric polarization of barium strontium titanate in the paraelectric state

Applied Physics Letters, 2002
The strain-gradient-induced polarization (flexoelectric effect) was investigated in Ba0.67Sr0.33TiO3 (BST) ceramic at temperatures above the 21 °C Curie point. At 23 °C the flexoelectric coefficient μ12 was more than one order of magnitude greater than the highest value measured in lead magnesium niobate ceramic.
Wenhui Ma, L. Eric Cross
openaire   +1 more source

Increase in the electric polarization in a multiferroic induced by the flexoelectric effect

JETP Letters, 2012
It has been shown that the electric polarization in multiferroic crystals exhibiting the magnetoelectric effect can be increased in the presence of the flexoelectric effect. The polarization in manganite-based perovskite-like multiferroics can be increased if the long axes of the rhombohedra formed upon the rhombohedral distortion of MnO6 octahedra can
S. A. Pikin, I. S. Lyubutin
openaire   +1 more source

Flexoelectric Polarization, Interactions of Longer Range and Multilayer Structures

Ferroelectrics, 2012
Flexoelectric interactions in antiferroelectric liquid crystals are a reason for effective interactions to more distant layers in systems where the polarizations in neighboring layers directly interact. In a presence of strong biquadratic coupling which favors uniplanar tilts, the system locks to commensurate structure.
openaire   +1 more source

Mechanical Control of Polar Patterns in Wrinkled Thin Films via Flexoelectricity

Physical Review Letters
Intriguing topological polar structures in oxide nanofilms have drawn growing attention owing to their immense potential applications in nanoscale electronic devices. Here, we report a novel route to mechanically manipulate polar structures via flexoelectricity in wrinkled thin films. Our results present a flexoelectric polar transition from a nonpolar
Hongxing Shang, Huiting Dong, Yihan Wu, Feng Deng, Xu Liang, Shuling Hu, Shengping Shen   +6 more
openaire   +2 more sources