Browsing School of Engineering by Author "MANNA, UTTAM"
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Anomalous dependence of response time on the electric field in an electroclinic liquid crystal with large induced tilt and polarization
VIJ, JAGDISH; MANNA, UTTAM; SONG, JANG-KUN (2009)We investigate the response time of an electroclinic liquid crystal with large induced tilt and polarization (de Vries smectic A*). The response time is found to increase with the increase in electric field up to a threshold ... -
Antiferroelectric dielectric relaxation processes and the interlayer interaction in antiferroelectric liquid crystals
VIJ, JAGDISH; SONG, JANG-KUN; FUKUDA, ATSUO; MANNA, UTTAM (2008)Antiphase relaxation process of antiferroelectric phase is investigated in binary mixtures of antiferroelectric and ferroelectric liquid crystalline compounds. It is found that the frequency of the antiphase mode ranges ... -
Effect of cell surfaces on the stability of chiral smectic- C phases
VIJ, JAGDISH; MANNA, UTTAM; SONG, JANG-KUN (2008)The effect of surfaces on the stability of smectic-C* (SmC*) variant phases is investigated. The results obtained using dielectric spectroscopy by varying the cell thickness show that the temperature ranges of SmC<sub>al ... -
Electric field induced biaxiality and the electro-optic effect in a bent-core nematic liquid crystal
VIJ, JAGDISH; PANARIN, YURI; MANNA, UTTAM (2010)We report the observation of a biaxial nematic phase in a bent-core molecular system using polarizing microscopy, electro-optics, and dielectric spectroscopy, where we find that the biaxiality exists on a microscopic scale. ... -
Electric-field-dependent dielectric response in the de Vries-type smectic- A* phase possessing local orientational order with nanoscale correlation length
VIJ, JAGDISH; MANNA, UTTAM; SONG, JANG-KUN (2008)The dielectric strength is shown to increase and the relaxation frequency to decrease for a large temperature range up to a certain value of the electric field in the smectic-A* phase. This behavior contrasts to that ... -
Electro-optic and dielectric study of the de Vries-type smectic- A phase exhibiting transitions to smectic- CA and smectic- C phases
PANARIN, YURI; VIJ, JAGDISH; FUKUDA, ATSUO; MANNA, UTTAM; SONG, JANG-KUN (2008)Mixtures of different compositions of an antiferroelectric liquid crystal compound that exhibits direct smectic-A Sm-A -smectic-CA Sm-CA transition with a ferroelectric liquid crystal compound that exhibits Sm-A -smectic-C ... -
Mechanism of field-induced unwinding of SmC* helix and biasfield dependencies of dielectric permittivity and effective polarization
VIJ, JAGDISH; SONG, JANG-KUN; MANNA, UTTAM (2008)We propose an unwinding model based on helical fractures confirmed by spectroscopic and microscopic observations. This model combined with the fixed helical pitch can explain the various physical phenomena observed in ... -
X-ray diffraction study of ferroelectric and antiferroelectric liquid crystal mixtures exhibiting de Vries SmA∗-SmC∗ transitions
VIJ, JAGDISH; MANNA, UTTAM; FUKUDA, ATSUO (2010)In this Rapid Communication, results on smectic layer thickness, using synchrotron radiation x-ray diffraction, for different mixtures of ferroelectric and antiferroelectric liquid crystals are given. We find that with ...