Dielectric investigation of the liquid crystal compound with the directSmA*–SmC_A* phase transition

ABSTRACT

New compound showing a direct SmA*–SmC_A* phase transition was synthesised. As far as authors know there are a few pure compounds showing para- and antiferroelectric phases without SmC* between them. Direct current (DC) field applied into a planar-oriented cell induces ferroelectric SmC* phase in an investigated compound. Typical for SmC*, Goldstone mode starts to be detectable. DC field also shifts down the temperature of a SmC_A* phase creation. Moreover, modes in the appearing antiferroelectic phase are enhanced by DC field. This paper shows and discusses relations between modes detected in SmA*, SmC_A* and SmC* (SmC* phase – nucleated by DC field) phases. Parameters of observed modes are calculated using the Cole–Cole relaxation model and a calculation procedure useful especially for high frequency relaxations (higher than 200 kHz).

GRAPHICAL ABSTRACT

KEYWORDS:

• Soft mode
• Goldstone mode
• relaxation frequency
• antiferroelectic liquid crystal
• dielectric spectroscopy
• Cole–Cole model

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was done in 2015 under financial support from the Polish Ministry of Sciences and Higher Education, Key Project POIG.01.03.01−14−016/08 ‘New photonic materials and their advanced application’.