Positional order in the smectic-G, -F, and -C layers of HBHA
نویسنده
چکیده
2014The positional order correlation length « 03BE~ » parallel to the smectic (Sm) layers in the G, F and C phases of HBHA (7O.6) has been measured by X-ray diffraction. In the Sm-G phase its value is limited by crystallite size and lies between 1200-1500 A. At the Sm-G to -F transition 03BE ~ changes from 300 to 180 A with a temperature dependence predicted by a dislocation mediated melting model of 2D lattice. At the Sm-F to -C transition 03BE~ changes discontinuously. The Sm-C phase is found to have an unusually large correlation length (~ 50 Å), almost double of that in the Sm-A phase. J. Physique 44 (1983) 123-126 JANVIER 1983,
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