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Macroscopic optical effects in low concentration ferronematics

Macroscopic optical effects in low concentration ferronematics
Macroscopic optical effects in low concentration ferronematics
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
1744-683X
4742-4749
Podoliak, Nina
0908b951-00a7-48a5-bc82-631640910b9c
Buchnev, Oleksandr
60cdb0d2-3388-47be-a066-61b3b396f69d
Buluy, Oleksandr
5246dfdd-9bf7-41da-a99e-9c1adb9f1615
D'Alessandro, Giampaolo
bad097e1-9506-4b6e-aa56-3e67a526e83b
Kaczmarek, Malgosia
408ec59b-8dba-41c1-89d0-af846d1bf327
Reznikov, Yuriy
38896996-b353-4cc9-a82b-671883f56ba5
Sluckin, Timothy J.
8dbb6b08-7034-4ae2-aa65-6b80072202f6
Podoliak, Nina
0908b951-00a7-48a5-bc82-631640910b9c
Buchnev, Oleksandr
60cdb0d2-3388-47be-a066-61b3b396f69d
Buluy, Oleksandr
5246dfdd-9bf7-41da-a99e-9c1adb9f1615
D'Alessandro, Giampaolo
bad097e1-9506-4b6e-aa56-3e67a526e83b
Kaczmarek, Malgosia
408ec59b-8dba-41c1-89d0-af846d1bf327
Reznikov, Yuriy
38896996-b353-4cc9-a82b-671883f56ba5
Sluckin, Timothy J.
8dbb6b08-7034-4ae2-aa65-6b80072202f6

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, 7 (10), 4742-4749. (doi:10.1039/C1SM05051F).

Record type: Article

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

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Published date: 21 May 2011
Organisations: Mathematical Sciences, Physics & Astronomy, Quantum, Light & Matter Group

Identifiers

Local EPrints ID: 186121
URI: https://eprints.soton.ac.uk/id/eprint/186121
ISSN: 1744-683X
PURE UUID: f2a545db-1331-4592-8e36-1dbe79c8a729
ORCID for Nina Podoliak: ORCID iD orcid.org/0000-0002-3146-0355
ORCID for Giampaolo D'Alessandro: ORCID iD orcid.org/0000-0001-9166-9356
ORCID for Timothy J. Sluckin: ORCID iD orcid.org/0000-0002-9163-0061

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Date deposited: 12 May 2011 11:36
Last modified: 06 Dec 2019 01:40

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Author: Nina Podoliak ORCID iD
Author: Oleksandr Buchnev
Author: Oleksandr Buluy
Author: Yuriy Reznikov

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