Comparative dielectric parameters and conductivity mechanisms of pyridine-based rod-like liquid crystals

Yılmaz Canlı N., Ocak H., Okutan M., Karanlık G., Bilgin Eran B.

Phase Transitions, vol.93, no.8, pp.784-792, 2020 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 93 Issue: 8
  • Publication Date: 2020
  • Doi Number: 10.1080/01411594.2020.1781121
  • Journal Name: Phase Transitions
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, Aerospace Database, Chemical Abstracts Core, Communication Abstracts, Compendex, INSPEC, Metadex, Civil Engineering Abstracts
  • Page Numbers: pp.784-792
  • Keywords: Liquid crystal, impedance spectroscopy (IS), dielectric properties (DP), conductivity mechanism, SERIES, TRANSPORT
  • Yıldız Technical University Affiliated: Yes

Abstract

© 2020, © 2020 Informa UK Limited, trading as Taylor & Francis Group.In this study, the dielectric properties and ac conductivity mechanism of pyridine-based rod-like liquid crystals (LC1 and LC2), which show enantiotropic smectic A mesophase, have been investigated by impedance spectroscopy within the frequency interval of 1 kHz–2 MHz. The variation of real and imaginary component of dielectric constant with angular frequency has been investigated. The temperature-dependent absorption coefficient α, relaxation time τ o, dielectric strength value Δε, temperature-dependent changes on crystal, SmA and Iso phases have been given. These values were obtained by fitting the experimental results in ε ′-ω graph with the Cole-Cole equation real equation and Origin Pro Graph program. The frequency dependence of ac conductivities has also been analyzed. Different conductivity mechanisms, i.e. dc conductivity, correlated barrier hoping and quantum mechanical tunneling behaviors have been determined for different frequency regions.