Frequency variation of periodic distortion thresholds in a nematic liquid crystal

Abstract

Investigations are reported on the electric ® eld induced orientational transitions in the bend Fre  edericksz geometry under the action of a stabilizing magnetic ® eld. When the magnetic ® eld is strong enough, the deformation above electric threshold is periodic with the periodicity disappearing at a higher voltage. The alignment does not remain homeotropic below threshold and the sample exhibits pretransitional biaxiality. Every transition is discontinuous and accompanied by hysteresis. The expected form of scaling appears to hold for all the observed thresholds. The thresholds and the direction of the wave vector are frequency dependent, showing that the instability mechanism involves electrical conductivity.

Low-frequency response of ferronematic liquid crystal

“…The latter effect can be detected by optical means. We believe that the above physical features and estimates can be efficiently utilized as a guideline in search of the magnetotorsion mode predicted on currently operating facilities [3][4][5].…”