Weak Coupling Effect on the Magnetic Freedericksz Transition in a Ferronematic Liquid Crystal

Popov, Vladimir; Gilev, V. G.; Zakhlevnykh, A. N.

doi:10.1134/s1063783418070247

Cited by 4 publications

(4 citation statements)

References 14 publications

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“…Lowering the threshold magnetic field, at which the response of liquid crystal molecules begins, has been the intention, since the first paper devoted to liquid crystals doped with magnetic particles was published in 1970 [ 15 ]. Since then, the composites consisting of various liquid crystals and magnetic nanoparticles have been studied experimentally [ 2 , 3 , 4 , 16 , 17 ] and theoretically [ 18 , 19 , 20 , 21 , 22 ]. Multiple experimental papers have reported [ 2 , 3 , 4 , 16 ] about decreasing in threshold magnetic field observed in composites of various liquid crystals and magnetic nanoparticles, but it was shown that increasing the threshold of magnetic fields can occur as well [ 17 ].…”

Section: Introductionmentioning

confidence: 99%

“…Since then, the composites consisting of various liquid crystals and magnetic nanoparticles have been studied experimentally [2][3][4]16,17] and theoretically [18][19][20][21][22]. Multiple experimental papers have reported [2][3][4]16] about decreasing in threshold magnetic field observed in composites of various liquid crystals and magnetic nanoparticles, but it was shown that increasing the threshold of magnetic fields can occur as well [17]. The influence of nanoparticles depends on their properties, which are related to material, size, shape, concentration, etc.…”

Section: Introductionmentioning

confidence: 99%

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Fréedericksz Transitions in 6CB Based Ferronematics—Effect of Magnetic Nanoparticles Size and Concentration

et al. 2021

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In this paper, results acquired from capacitance measurements performed on composites based on nematic liquid crystal 4-cyano-40-hexylbiphenyl (6CB) and spherical iron oxide nanoparticles of various sizes are presented. Electric and magnetic Fréedericksz transitions, as well as structural transitions in combined electric and magnetic fields, were investigated. The obtained results showed the lowering of the threshold magnetic field with an increase in the volume concentration of nanoparticles. Estimations based on results obtained from measurements suggest soft anchoring between liquid crystal director and nanoparticles magnetization vector.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Fréedericksz Transitions in 6CB Based Ferronematics—Effect of Magnetic Nanoparticles Size and Concentration

et al. 2021

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“…In equation (40), if we set the value of σ to be infinitely large, then λ becomes π. Using equation (33), we find that:…”

Section: Case-i: Non-magnetic Nanoparticlesmentioning

confidence: 99%

“…Following the work of Burylov and Raikher [20,21], series of experimental [25,[30][31][32][33][34] and theoretical works [35][36][37][38][39] were carried out to understand the different aspect of a ferronematic state. These include phase diagrams, Freedericksz transition and the magnetic field induced shift in isotropic to nematic transition temperature.…”

Section: Introductionmentioning

confidence: 99%

Freedericksz transition in ferronematic liquid crystal under weak anchoring conditions

2021

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Freedericksz effect is investigated theoretically for a ferronematic liquid crystal, which is a colloidal suspension of ferromagnetic nanoparticles in a nematic fluid. Considering a splay type Freedericksz geometry, weak anchoring conditions are assumed at the cell boundaries. The specific nature of this anchoring reveals a rich variety of stable ferronematic phases, which include uniform, distorted and saturated states. Apart from weak anchoring conditions at the cell boundaries, soft planar anchoring is assumed for the mesogenic molecules at the surface of a nanoparticle. The interplay between these two anchoring phenomena along with Frank type elastic theory determine the values of Freedericksz threshold between various ferronematic states. It is found that compared to relatively strong anchoring for the mesogens both at the cell boundaries and at the surface of the nanoparticles, weak anchoring significantly reduces the Freedericksz threshold field. Landau theory is then utilized to understand the nature of transition between different ferronematic states. Based on the phenomenon of segregation effect, these transitions are found to be either first order or second order in nature. The present theory is also extended to non-ferromagnetic nanoparticles and significant reduction in Freedericksz threshold is obtained. Finally, these results are corroborated with experimental findings.

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Antiferromagnetic liquid-crystal suspensions of goethite nanorods: three mechanisms of magnetic field influence on orientational structure

Petrov,

Chupeev

2024

Eur. Phys. J. E

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Weak Coupling Effect on the Magnetic Freedericksz Transition in a Ferronematic Liquid Crystal

Cited by 4 publications

References 14 publications

Fréedericksz Transitions in 6CB Based Ferronematics—Effect of Magnetic Nanoparticles Size and Concentration

Fréedericksz Transitions in 6CB Based Ferronematics—Effect of Magnetic Nanoparticles Size and Concentration

Freedericksz transition in ferronematic liquid crystal under weak anchoring conditions

Antiferromagnetic liquid-crystal suspensions of goethite nanorods: three mechanisms of magnetic field influence on orientational structure

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