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Nonlinear Dielectric Relaxation Spectroscopy of Ferroelectric and Antiferroelectric Liquid Crystals

Research Project

Project/Area Number 03452092
Research Category

Grant-in-Aid for General Scientific Research (B)

Allocation TypeSingle-year Grants
Research Field 応用物理学一般(含航海学)
Research InstitutionThe University of Tokyo

Principal Investigator

HAYAKAWA Reinosuke (1992)  The University of Tokyo, Faculty of Engineering, Professor, 工学部, 教授 (00011106)

早川 禮之助  東京大学, 工学部, 教授 (70010717)

Co-Investigator(Kenkyū-buntansha) KIMURA Yasuyuki  The University of Tokyo, Faculty of Engineering,Assistant, 工学部, 助手 (00225070)
OKUMOTO Hajime  The University of Tokyo, Faculty of Engineering,Assistant, 工学部, 助手 (50224176)
Project Period (FY) 1991 – 1992
Project Status Completed (Fiscal Year 1992)
Budget Amount *help
¥6,200,000 (Direct Cost: ¥6,200,000)
Fiscal Year 1992: ¥1,900,000 (Direct Cost: ¥1,900,000)
Fiscal Year 1991: ¥4,300,000 (Direct Cost: ¥4,300,000)
KeywordsNonlinear Dielectric Relaxation Spectroscopy / Ferroelectric Liquid Crystals / Antiferroelectric Liquid Crystals / Goldstone Mode / 非線形誘電緩和スペクトロスコピ- / ゴ-ルドストンモ-ド
Research Abstract

We developed the measurement system for the nonlinear dielectric relaxation spectrum in a wide frequency range and with high accuracy. This system consists of the wave generator, the charge amplifier, the digital storage oscilloscope and the personal computer. We measured the nonlinear spectra of some Ferroelectric Liquid Crystals (FLCs) in the SmC^* phase by use of this system. The obtained nonlinear dielectric constants of FLCs are much larger in magnitude by several decades than those obtained for ferroelectric polymers. The fact that the higher-order nonlinear spectrum has a counterpart in the linear one shows that the nonlinear mode is originated from the fluctuation of the helical structure, called the Goldstone mode. The negative sign of the third-order nonlinear dielectric constant implies that the origin of this nonlinearity is the orientational saturation of the dipolemoments by the applied electric field. The third-order dielectric constant is almost independent of the temperature in the SmC^* phase and shows the critical behavior in the vicinity of the SmA-SmC^* phase transition temperature. The critical behavior appears more remarkably in the nonlinear spectrum than in the linear one. The linear and nonlinear spectra are explainable by the phenomenological theory. We also measured the nonlinear dielectric spectra for an antiferroelectric liquid crystal MHPOBC in various smectic phases. In the ferrielectric phase, for example, we found a phase transition from a ferri-state to a ferro-state induced by the increase of electric field. From the saturated value of polarization in both the states, we estimated the molecular arrangement in the ferrielectric phase. Through the present study, this spectroscopy is found to be a useful tool to obtain the information on the structure and dynamics of the electro-active smectic liquid crystals.

Report

(3 results)
  • 1992 Annual Research Report   Final Research Report Summary
  • 1991 Annual Research Report
  • Research Products

    (10 results)

All Other

All Publications (10 results)

  • [Publications] Yasuyuki Kimura: "Nonlinear Dielectric Relaxation Spectra Calculated with a Free Rotation Model of the Dipole Moment" Japanese Journal of Applied Physics. 31. 3387-3391 (1992)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1992 Final Research Report Summary
  • [Publications] Yasuyuki Kimura: "Non-linear Dielectric Spectra of Fewoelectric Liquid Crystals" Liquid Crystals.

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1992 Final Research Report Summary
  • [Publications] Yasuyuki Kimura: "Experimental Study of Nonlinear Dielectric Relaxation Spectra of Fewoelectric Liquid Crystals on the Smectic C* Phase" Japanese Journal of Applied Physics.

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1992 Final Research Report Summary
  • [Publications] Yasuyuki Kimura and Reinosuke Hayakawa: "Nonlinear Dielectric Relaxation Spectra Calculated with a Free Rotation Model of the Dipole Moment" Japanese Journal of Applied Physics. Vol.31. 3387 (1992)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1992 Final Research Report Summary
  • [Publications] Yasuyuki Kimura and Reinosuke Hayakawa: "Non-linear Dielectric Spectra of Ferroelectric Liquid Crystals" Liquid Crystals.

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1992 Final Research Report Summary
  • [Publications] Yasuyuki Kimura and Reinosuke Hayakawa: "Experimental Study of Nonlinear Dielectric Relaxation Spectra of Ferroelectric Liquid Crystals in the Smectic C^* Phase" Japanese Journal of Applied Physics.

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1992 Final Research Report Summary
  • [Publications] Yasuyuki Kimura: "Nonlinear Dielectric Relaxation Spectra Calculated with a Free Rotation Model of the Dipole Moment" Japanese Journal of Applied Physics. 31. 3387-3391 (1992)

    • Related Report
      1992 Annual Research Report
  • [Publications] Yasuyuki Kimura: "Non-linear Dielectric Spectra of Fenoelectric Liquid Crystals" Liquid Crystals.

    • Related Report
      1992 Annual Research Report
  • [Publications] Yasuyuki Kimura: "Nonlinear Dielectric Relaxation Spectra Calculated with Free Rotational Model of Dipde Moment" Japanese Journal of Applied Physics.

    • Related Report
      1991 Annual Research Report
  • [Publications] Yasuyuki Kimura: "Expevimeutal Study of Nonlinear Dielectric Relaxation Spectra of Ferroelectric Liquid Crystals" Japanese Journal of Applied Physics.

    • Related Report
      1991 Annual Research Report

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Published: 1991-04-01   Modified: 2017-10-06  

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