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Measuring Magnetically-Tuned Ferroelectric Polarization in Liquid Crystals
Published on: August 15, 2018
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Ferroelectric-Ferroelastic Phase Transition in a Nematic Liquid Crystal
Nerea Sebastián1, Luka Cmok1, Richard J Mandle2
1Jožef Stefan Institute, SI-1000 Ljubljana, Slovenia.
Physical Review Letters
|February 8, 2020
Summary
Ferroelectric ordering in liquids drives the formation of a novel splay nematic liquid-crystalline phase. This ferroelectric phase transition is linked to orientational ferroelasticity and flexoelectric coupling.
Area of Science:
- Physics
- Materials Science
- Liquid Crystals
Background:
- Ferroelectric ordering in liquids is a fundamental physics question.
- Understanding liquid crystal phases is crucial for materials science.
Purpose of the Study:
- To investigate the link between molecular ferroelectric ordering and the formation of the splay nematic liquid-crystalline phase.
- To characterize the ferroelectric phase transition and its associated phenomena.
Main Methods:
- Dielectric spectroscopy to analyze phase transitions.
- Second harmonic generation imaging to prove polarity.
- Polarized optical microscopy to confirm modulation period.
Main Results:
- Ferroelectric ordering of molecules induces the splay nematic phase.
- The uniaxial to splay nematic transition exhibits ferroelectric characteristics.
- Flexoelectric coupling drives an orientational ferroelastic transition.
- Splay modulation period determined to be 5-10 microns.
Conclusions:
- Ferroelectric ordering is the driving force behind the splay nematic phase formation.
- The observed phenomena are consistent with a Landau-de Gennes macroscopic theory.
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