Europhys. Lett.
Volume 73, Number 1, January 2006
Page(s) 49 - 54
Section Condensed matter: structural, mechanical and thermal properties
Published online 23 November 2005
Europhys. Lett., 73 (1), pp. 49-54 (2006)
DOI: 10.1209/epl/i2005-10348-y

Dislocation-loop-mediated smectic melting

P. Moreau1, L. Navailles1, J. Giermanska-Kahn1, O. Mondain-Monval1, F. Nallet1 and D. Roux1, 2

1  Centre de recherche Paul-Pascal, CNRS - 115 avenue Albert-Schweitzer F-33600 Pessac, France
2  Saint-Gobain - Les Miroirs, 18 avenue d'Alsace, F-92096 La Défense Cedex, France

received 26 August 2005; accepted in final form 25 October 2005
published online 23 November 2005

We report the direct observation, using freeze-fracture transmission electron microscopy, of topological melting in a lyotropic system in the vicinity of a smectic-cholesteric (N*) phase transition. The proliferation of dislocations leads to at least one, and possibly two intermediate phases, characterised by orientational ordering of the dislocation loops and the subsequent unbinding of the screw-dislocation lines.

61.30.Jf - Defects in liquid crystals.
64.70.Md - Transitions in liquid crystals.
61.30.St - Lyotropic phases.

© EDP Sciences 2005