Research output: Contribution to Journal/Magazine › Journal article › peer-review
Article number | 56001 |
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<mark>Journal publication date</mark> | 06/2008 |
<mark>Journal</mark> | EPL |
Issue number | 5 |
Volume | 82 |
Number of pages | 6 |
Publication Status | Published |
<mark>Original language</mark> | English |
Raman Scattering was used to investigate biaxiality in the nematic phase formed by the bent-core material, C5-Ph-ODBP-Ph-OC12. Linearly polarised light was normally incident on a homogeneously aligned sample, and the depolarisation ratio was measured over a 360 degrees rotation of the incident polarisation for the Raman-active phenyl stretching mode. By modeling the bent-core structure and fitting to the depolarisation data, both the uniaxial ([P(200)] and [P(400)]) and biaxial ([P(220)], [P(420)] and [P(440)]) order parameters, are deduced. We show unequivocally the presence of a uniaxial to biaxial nematic phase transition approximately 30 degrees C above the underlying smectic phase. Further, we report the temperature evolution of the biaxial and uniaxial order parameters, which increase in magnitude continuously with reducing temperature, reaching values of 0.1, -0.15 and -0.18 for [P(220)], [P(420)] and [P(440)], respectively. Copyright (c) EPLA, 2008.