Light scattering from liquid crystal director fluctuations in steady magnetic fields up to 25 tesla

Challa, Pavan Kumar; Curtiss, O.; Williams, Jarrod; Twieg, Robert J.; Toth, J.; McGill, Stephen; Jákli, Antal; Gleeson, J. T.; Sprunt, Samuel

doi:10.1103/physreve.86.011708

Cited by 5 publications

(5 citation statements)

References 29 publications

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“…Besides optical microscopy, only a few other in situ techniques are available to track magnetic particles. In situ dynamic light scattering 45 or in situ confocal microscopy 46 are suitable alternatives, which also have the potential of tracking nanometer-sized objects. The problem of decreasing magnetic energy upon miniaturization of magnetic objects is resolved by the employment of higher magnetic elds (i.e.…”

Section: Inhomogeneous Magnetic Elds and Ferromagnetsmentioning

confidence: 99%

Manipulation of micro- and nanostructure motion with magnetic fields

et al. 2014

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In this review we will focus on how magnetic fields can be used to manipulate the motion of various micro- and nanostructures in solution. We will distinguish between ferromagnetic, paramagnetic and diamagnetic materials. Furthermore, the use of various kinds of magnetic fields, such as homogeneous, inhomogeneous and rotating magnetic fields, is discussed. To date most research has focused on the use of ferro- and paramagnetic materials, but here we also describe the possibilities of magnetic manipulation of diamagnetic materials. Since the vast majority of soft matter is diamagnetic, this paves the way for many new applications to manipulate the motion of micro- and nanostructures.

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Section: Inhomogeneous Magnetic Elds and Ferromagnetsmentioning

confidence: 99%

Manipulation of micro- and nanostructure motion with magnetic fields

et al. 2014

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“…The materials were loaded into glass sandwich cells treated for planar alignment with cell spacing d = 10µm (KA(0.2)) or 5µm (CB7CB). The cells were held in a temperature controlled oven which was placed at the center of the vertical bore of the 25T split-helix resistive solenoid magnet [21] at the National High Magnetic Field Laboratory (NHMFL). The two materials were studied using the optical arrangement depicted in Figure 1.…”

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confidence: 99%

Twist-bend nematic liquid crystals in high magnetic fields

et al. 2014

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We present magneto-optic measurements on two materials that form the recently discovered twist-bend nematic (N_{tb}) phase. This intriguing state of matter represents a fluid phase that is orientationally anisotropic in three directions and also exhibits translational order with periodicity several times larger than the molecular size. N_{tb} materials may also spontaneously form a visible, macroscopic stripe texture. We show that the optical stripe texture can be persistently inhibited by a magnetic field, and a 25T external magnetic field depresses the N-N_{tb} phase transition temperature by almost 1{∘}C. We propose a quantitative mechanism to account for this shift and suggest a Helfrich-Hurault-type mechanism for the optical stripe formation.

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“…For practical applications, that is an electric field, but a magnetic field could also be used. 1,2 For display applications, the electrodes need to be transparent. Indium tin oxide (ITO) has been a preferred material for this, because of its combination of good electrical conductivity, optical transparency and chemical resistance to moisture, but its main drawback is cost.…”

Section: Introductionmentioning

confidence: 99%

Liquid crystal devices with continuous phase variation based on high-permittivity thin films

2016

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Most liquid crystal devices use transparent conductive electrodes such as indium tin oxide (ITO) to apply a potential difference in order to achieve electro-optic switching. As an alternative, we study a device with narrow metallic electrodes in combination with dielectric layers with large dielectric permittivity. In this approach the applied voltage can be a continuous function of the lateral distance from the electrode line. Simulations for a one-dimensional beam-steering device show that the switching of the liquid crystal (LC) director depends indeed on the distance from the addressing electrodes and on the value of the relative permittivity. We show that in a device with electrodes spaced 60 μm apart, the LC director halfway between the electrodes shows a considerable reorientation, when a dielectric layer with permittivity of r = 550 is used, whereas no reorientation is observed for the uncoated reference sample at the same voltage. An added advantage is that the proposed configuration only contains dielectric materials, without resistive losses, which means that almost no heat is dissipated. This indicates that this technology could be used in low-power LC devices. The results show that using dielectric thin films with high relative permittivity in liquid crystal devices could form a cost-efficient and low-power alternative to many LC technologies where a gradient electric field is desirable

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Light scattering from liquid crystal director fluctuations in steady magnetic fields up to 25 tesla

Cited by 5 publications

References 29 publications

Manipulation of micro- and nanostructure motion with magnetic fields

Manipulation of micro- and nanostructure motion with magnetic fields

Twist-bend nematic liquid crystals in high magnetic fields

Liquid crystal devices with continuous phase variation based on high-permittivity thin films

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