Effects of flow on the dynamics of a ferromagnetic nematic liquid crystal

Tilen Potisk (Author), Harald Pleiner (Author), Daniel Svenšek (Author), Helmut R. Brand (Author)

Abstract

We investigate the effects of flow on the dynamics of ferromagnetic nematic liquid crystals. As a model we study the coupled dynamics of the magnetization, M, the director field, n, associated with the liquid crystalline orientational order and the velocity field v. We evaluate how simple shear flow in a ferromagnetic nematic is modified in the presence of small external magnetic fields and we make experimentally testable predictions for the resulting effective shear viscosity: an increase by a factor of two in a magnetic field of about 20 mT. Flow alignment, a characteristic feature of classical uniaxial nematic liquid crystals, is analyzed for ferromagnetic nematics for the two cases of a magnetization in or perpendicular to the shear plane. In the former case we find that small in-plane magnetic fields are suffcient to suppress tumbling and that thus the boundary between flow alignment and tumbling can be controlled easily. In the latter case we furthermore find a possibility of flow alignment in a regime for which one obtains tumbling for the pure nematic component. We derive the analogues of the three Miesowicz viscosities well-known from usual nematic liquid crystals, corresponding to nine different configurations. Combinations of these can be used to determine several dynamic coeffcients experimentally.

Keywords

fizika kondenzirane snovi;nematski tekoči kristali;feromagnetni tekoči kristali;dinamika tekočin;kompleksne tekočine;condensed matter physics;nematic liquid crystals;ferromagnetic liquid crystals;fluid dynamics;complex fluids;

Data

Language:	English
Year of publishing:	2018
Typology:	1.01 - Original Scientific Article
Organization:	UL FMF - Faculty of Mathematics and Physics
UDC:	532.5:538.9
COBISS:	3200356
ISSN:	2470-0045
Views:	16464
Downloads:	502
Average score:	0 (0 votes)
Metadata:

Other data

Secondary language:	Slovenian
Secondary keywords:	fizika kondenzirane snovi;nematski tekoči kristali;feromagnetni tekoči kristali;dinamika tekočin;kompleksne tekočine;
Pages:	str. 042705-1-042705-13
Volume:	ǂVol. ǂ97
Issue:	ǂiss. ǂ4
Chronology:	2018
DOI:	10.1103/PhysRevE.97.042705
ID:	10942260