Depolarization field and ionic effects on the bistability of surface-stabilized ferroelectric liquid-crystal devices

Yang, K. H.; Chieu, T. C.; Osofsky, S.

doi:10.1063/1.102121

Cited by 80 publications

(22 citation statements)

References 4 publications

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“…It is known that the polarization and ionic charges, accumulated on the interfaces between the FLC medium and alignment layers, tend to partially screen the external applied field and generate a depolarization field that reverses the spontaneous polarization when the external field is switched off. 24 In our case, the conductivity near room temperature is low, which causes the charges to accumulate on the interfaces between the FLC and the alignment layer. This develops a depolarization field, which degrades memory effect, and hence no memory effect was observed at room temperature.…”

Section: Resultsmentioning

confidence: 99%

Memory effect near transition temperature in Sm C∗ phase in nonsurface stabilized ferroelectric liquid crystals

Coondoo

Malik

Choudhary

et al. 2008

Journal of Applied Physics

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Memory behavior in the ferroelectric liquid crystal ͑FLC͒ material, Felix 17/100, has been investigated by electro-optical, dielectric, and hysteresis methods at different temperatures ranging from room temperature to near ferro-paraelectric phase transition. Memory effect has been observed in the studied material near the transition temperature in Sm C ‫ء‬ phase in the cells having thickness greater than the pitch value of the material. This is in contrast to the memory effect observed in conventional FLCs where thickness of the cell has to be less than the pitch value of the material. Electrical conductivity measurements elucidate that the steep increase in the conductivity near the transition temperature in Sm C ‫ء‬ phase enhances the motion of free ions and probably weakens the depolarization field in the material, thereby showing memory effect.

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Section: Resultsmentioning

confidence: 99%

Memory effect near transition temperature in Sm C∗ phase in nonsurface stabilized ferroelectric liquid crystals

Coondoo

Malik

Choudhary

et al. 2008

Journal of Applied Physics

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“…Previous reports on bistability of FLC device reveals that, it is greatly inuenced by the impurity ions containing in it. 38 In spite of its mobility, impurity ions are always detrimental to the bistability of FLCs. The ionic impurities accumulated in between the alignment layer and FLC medium enhances the depolarization eld and accelerate the decay of bistability when the electric eld is switched off.…”

Section: Resultsmentioning

confidence: 99%

Low-voltage electro-optical memory device based on NiO nanorods dispersed in a ferroelectric liquid crystal

et al. 2016

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We present a low voltage driven electro-optical memory device fabricated by dispersing nano-sized nickel oxide (nNiO) composed of short length nanorods into a ferroelectric liquid crystal (FLC) host material. The nNiO/FLC composite showed a tremendous decrease in saturation voltage compared to the pristine FLC material along with non-volatile memory behavior which is confirmed through dielectric spectroscopy, polarized optical microscopy and electro-optical response methods. This drop off in saturation voltage is due to the fast alignment of dipolar nNiO and mesogens in the nNiO/FLC composite along the direction of the applied electric field and reduced screening effect. The non-volatile memory behavior of the composite is attributed to the reduction in the depolarization field by adsorption of impurity ions onto the surface of nNiO, which is verified through dielectric spectroscopy and electrical conductivity measurements. These studies pave the way for fabricating non-volatile, low power electro-optical memory devices for advanced information storage applications.

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“…An additional factor that may contribute to the lack of bistability is the presence of ions, which are known to adversely influence bistable states. 30 The experimental apparatus is illustrated in Figure 2. We use an Ar+ laser at 514 nm that is split into two be%ns of 15 mW each.…”

Section: Experimental Methodsmentioning

confidence: 99%

<title>Photorefractivity in ferroelectric liquid crystals</title>

Wiederrecht

Wasielewski²,

Fuller³

2000

SPIE Proceedings

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The first observation of photorefiactivity in ferroelectric liquid crystals (flcs) is reported. The flcs are doped with the easily oxidized chromophore perylene, which also functions as the sensitizer.The electron acceptor di-butylpyromellitirnide is added to induce photoconductivity through an efficient intermolecular electron transfer reaction to produce mobile ions. A strong dependence on the orientation of the wavevector of the optical intefierence pattern and polarization of the writing beams relative to the orientation of the flc molecules is observed. The results are interpreted as an orientational photorefiactive effect in which the net polarization of the flc couples linearly to the space-charge field as opposed to nematic liquid crystals in which the dielectric anisotropy couples to the square of the space charge field.

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Depolarization field and ionic effects on the bistability of surface-stabilized ferroelectric liquid-crystal devices

Abstract: The bistability of the surfacestabilized ferroelectric liquidcrystal effect in electrically reoriented chevron structures

Cited by 80 publications

References 4 publications

Memory effect near transition temperature in Sm C∗ phase in nonsurface stabilized ferroelectric liquid crystals

Memory effect near transition temperature in Sm C∗ phase in nonsurface stabilized ferroelectric liquid crystals

Low-voltage electro-optical memory device based on NiO nanorods dispersed in a ferroelectric liquid crystal

<title>Photorefractivity in ferroelectric liquid crystals</title>

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