Macroscopic optical effects in low concentration ferronematics
Podoliak, Nina, Buchnev, Oleksandr, Buluy, Oleksandr, D'Alessandro, Giampaolo, Kaczmarek, Malgosia, Reznikov, Yuriy and Sluckin, Timothy J. (2011) Macroscopic optical effects in low concentration ferronematics. Soft Matter(doi:10.1039/c1sm05051f)
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Description/Abstract
We present a detailed experimental and theoretical study of the optical response of suspensions of ferromagnetic nanoparticles (“ferroparticles”) in nematic liquid crystals (“ferronematics”), concentrating on the magnetic field-induced Frederiks transition. Even extremely low ferroparticle concentrations (at a volume fraction between 2 × 10−5 and 2 × 10−4), induce a significant additional ferronematic linear response at low magnetic field (<100 G) and a decrease in the effective magnetic Frederiks threshold. The experimental results demonstrate that our system has weak ferronematic behavior. The proposed theory takes into account the nematic diamagnetism and assumes that the effective magnetic susceptibility, induced by the nanoparticles, no longer dominates the response. The theory is in good agreement with the experimental data for the lowest concentration suspensions and predicts the main features of the more concentrated ones. The deviations observed in these cases hint at extra effects due to particle aggregation, which we have also observed directly in photographs.
| Item Type: | Article |
|---|---|
| ISSN: | 1744-683 (print) 1744-6848 (electronic) |
| Subjects: | Q Science > QA Mathematics Q Science > QB Astronomy Q Science > QC Physics |
| Divisions: | University Structure - Pre August 2011 > School of Mathematics > Applied Mathematics University Structure - Pre August 2011 > School of Physics and Astronomy > Quantum, Light and Matter |
| ePrint ID: | 181421 |
| URI: | http://eprints.soton.ac.uk/id/eprint/181421 |
| Deposited On: | 18 Apr 2011 14:08 |
| Last Modified: | 21 May 2012 17:55 |
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