Impedance Spectroscopy

Yadav, Neelam; Dhar, Ravindra

doi:10.1007/978-981-33-6084-6_19

Cited by 9 publications

(3 citation statements)

References 63 publications

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“…Broadband dielectric spectroscopy is an effective technique to study the various relaxation phenomena occurring inside materials [51] . This method measures the response of electric dipoles to a weak external electric field and can detect changes in the structure of the mesogenic compounds.…”

Section: Resultsmentioning

confidence: 99%

“…Broadband dielectric spectroscopy is an effective technique to study the various relaxation phenomena occurring inside materials. [51] This method measures the response of electric dipoles to a weak external electric field and can detect changes in the structure of the mesogenic compounds. This method is superior to other electro-optical techniques used for detecting relaxation mechanisms in LCs since the structure of the phase is not significantly disturbed while taking measurements.…”

Section: Dielectric Spectroscopymentioning

confidence: 99%

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Nematic Phase of Polar Unsymmetrical Bent‐Core Molecules

et al. 2023

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In liquid crystalline systems, the presence of polar groups at lateral or terminal positions is fundamentally and technologically important. Bent-core nematics composed of polar molecules with short rigid cores usually exhibit highly disordered mesomorphism with some ordered clusters that favourably nucleate within. Herein, we have systematically designed and synthesized two new series of highly polar bent-core compounds comprised of two unsymmetrical wings, highly electronegative À CN and À NO 2 groups at one end, and flexible alkyl chains at the other end. All the compounds showed a wide range of nematic phases composed of cybotactic clusters of smectic-type (N cyb ). The birefringent microscopic textures of the nematic phase were accompanied by dark regions. Further, the cybotactic clustering in the nematic phase was characterized via temperature-dependent XRD studies and dielectric spectroscopy. Besides, the birefringence measurements demonstrated the ordering of the molecules in the cybotactic clusters upon lowering the temperature. DFT calculations illustrated the favourable antiparallel arrangement of these polar bent-core molecules as it minimizes the large net dipole moment of the system.

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Section: Resultsmentioning

confidence: 99%

Section: Dielectric Spectroscopymentioning

confidence: 99%

Nematic Phase of Polar Unsymmetrical Bent‐Core Molecules

et al. 2023

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“…Dielectric spectroscopy (DS) [17] is a powerful methodology for studying the dipolar response to a weak electric field without causing much disturbance to the material, and for exploring the relaxation phenomena in the liquid crystalline nematic phase under investigation. Dielectric spectroscopy has been used for investigating ferroelectric nematics: in investigating fluoro compounds with the objective of making a preliminary assignment of the processes in DIO [18].…”

Section: Introductionmentioning

confidence: 99%

Collective Relaxation Processes in Nonchiral Nematics

et al. 2023

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Nematic–nematic transitions in a highly polar nematic compound are studied, in thick cells in which the molecules are aligned parallel to the substrates but perpendicular to the applied electric field, using dielectric spectroscopy in the frequency range 1 Hz to 10 MHz over a wide temperature range. The studied compound displays three nematic phases under cooling from the isotropic phase: ubiquitous nematic N; high polarizability NX; and ferroelectric nematic NF. Two collective processes were observed. The dielectric strength and relaxation frequency of one of the processes P2 showed a dependence on the thickness of the cell. The process P1 is the amplitude mode, while the process P2 is the phason mode.

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