Abstract
We construct a theoretical model for a thermotropic ferronematic (magnetic liquid crystal colloid) in an asymmetric twisted nematic cell, subject to in-plane magnetic fields. At low colloidal concentrations, the nematic director [ncirc] is unchanged by strong fields, the magnetic director [mcirc] principally responds to its coupling to [ncirc], and the suspension density peaks sharply where [mcirc] and H are co-aligned. At higher concentrations feedback between [mcirc] and [ncirc] aligns [ncirc] over a significant part of the cell, and the suspension divides into a region where [ncirc] is parallel to H , and a region where it is not. We also make calculations of the optical properties of this cell.
Acknowledgments
This work was done partially under U.S. Army International Technology Center-Atlantic Grant W911NF-08-1-0037 and NATO Grant CBP.NUKR.CLG.981968. We are grateful to these organisations for their financial support. We further acknowledge discussion with K. S. Thomas, G. D'Alessandro and N. Podoliak on theoretical questions, and with Yu. Reznikov and M. Kaczmarek on the experimental background.