N. W. Roberts et al 2005 Europhys. Lett. 72 976 doi:10.1209/epl/i2005-10336-3
N. W. Roberts1, S. Jaradat1, L. S. Hirst1,2, M. S. Thurlow1, Y. Wang1, S. T. Wang3, Z. Q. Liu3, C. C. Huang3, J. Bai4, R. Pindak4 and H. F. Gleeson1
Show affiliationsHigh-resolution resonant X-ray diffraction experiments have been performed on free-standing films of two selenium-containing antiferroelectric liquid-crystal mixtures. Optical studies had indicated that both mixtures exhibit exceptionally wide intermediate phases, over a total range of > 9 K. Through the structural information obtained from the resonant scattering data, we confirm that the intermediate phases of these mixtures show both 3-layer and 4-layer structural periodicities. Moreover, due to the stability of these phases, we report for the first time the temperature dependence of both the helicoidal pitch and distortion angle in the 3-layer phases deduced using the resonant X-ray technique. Analysis using an extension of the theory set out by Levelut and Pansu (Levelut A-M. and Pansu B., Phys. Rev. E, 60 (1999) 6803) shows that over the temperature ranges measured, the pitch changes linearly as a function of temperature whilst the distortion angle remains constant.
83.80.Xz Liquid crystals: nematic, cholesteric, smectic, discotic, etc.
61.30.Eb Experimental determinations of smectic, nematic, cholesteric, and other structures
Issue 6 (December 2005)
Received 19 August 2005, accepted for publication 19 October 2005, in final form 19 October 2005
Published 23 November 2005
N. W. Roberts et al 2005 Europhys. Lett. 72 976
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