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DY: Fachverband Dynamik und Statistische Physik
DY 21: Complex Fluids and Colloids II (joint session CPP/DY)
DY 21.1: Vortrag
Dienstag, 13. März 2018, 09:30–09:45, C 264
Effective Landau description of ferronematics — •Grigorii Zarubin1,2, Markus Bier1,2, and Siegfried Dietrich1,2 — 1Max Planck Institute Int. Sys. — 2University of Stuttgart, Germany
A ferromagnetic phase of anisotropic particles suspended in a nematic liquid crystal (NLC) was predicted as early as 1970 [1]. A recent experimental realization [2] confirmed that a dilute suspension of magnetic platelets in NLC forms ferromagnetic phase which is susceptible to weak magnetic fields. In this work we develop a Landau-like description of such a suspension starting from a microscopic model. Our functional represents an expansion in powers of two spatially varying fields: i) magnetization field and ii) director field and their cross terms. Using this result we can compare our theory to the one proposed in [2], in particular we have an access to the effective coupling coefficient between magnetization and director field which provides a way to estimate coupling of the director to the surface of the single platelet experimentally.
[1] F. Brochard and P.G. de Gennes, J. Physique 31, 691 (1970).
[2] A. Mertelj, D. Lisjak, M. Drofenik and M. Copic, Nature 504, 237 (2013).