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Titre du document / Document title

Nanoparticle aggregation and relaxation effects in ferrofluids studied through anisotropic light scattering

Auteur(s) / Author(s)

RABLAU Corneliu (1) ; VAISHNAVA Prem (1) ; SUDAKAR Chandran (2) ; TACKETT Ronald (2) ; LAWES Gavin (2) ; NAIK Ratna (2) ;

Affiliation(s) du ou des auteurs / Author(s) Affiliation(s)

(1) Department of Physics, Kettering University, 1700 West Third Ave, Flint, MI, 48504, ETATS-UNIS
(2) Department of Physics and Astronomy, Wayne State University, Detroit, MI, 48201, ETATS-UNIS

Résumé / Abstract

We have investigated the aggregation and dissociation dynamics of 6-nm size Fe3O4 nanoparticles coated by tetra methyl ammonium hydroxide (TMAH) and the same size γ-Fe2O3 nanoparticles precipitated inside an alginate hydrogel matrix, both in aqueous suspensions, using dc magnetic-field-induced time-dependent light scattering patterns. For the Fe3O4 ferrofluid, a strong anisotropy in light scattering was observed for light propagating perpendicular to the magnetic field. This behavior is attributed to the aggregation of the nanoparticles into chain-like and column-like structures oriented parallel to the magnetic field. A significantly different behavior is observed for the aqueous suspension of γ-Fe2O3 nanoparticles precipitated in alginate hydrogel, for which the application of the dc magnetic field produced little to no change in the light scattering patterns. We attribute this difference to the constrained random distribution of γ-Fe2O3 nanoparticles precipitated in the alginate matrix. Correlating the results from this investigation with our previous study of magneto-thermal measurements in ac fields [Vaishnava et al., J. Appl. Phys. 102, 063914 (2007)], we conclude that for a ferrofluid to exhibit significant thermal effects under an ac magnetic field, it should exhibit optical anisotropy by developing a chain like structure under the influence of a dc magnetic field.

Revue / Journal Title

Proceedings of SPIE, the International Society for Optical Engineering    ISSN  0277-786X   CODEN PSISDG 

Source / Source

Congrès
Plasmonics :   ( metallic nanostructures and their optical properties VI )  ( 10-14 August 2008, San Diego, California, USA )
Plasmonics No6, San Diego CA , ETATS-UNIS (2008)
2008  , vol. 7032, pp. 70320Z.1-70320Z.12[Note(s) : 1 v. (various pagings), ] (33 ref.) ISBN 0-8194-7252-2 ; 978-0-8194-7252-6 ;  Illustration : Illustration ;

Langue / Language

Anglais

Editeur / Publisher

Society of Photo-Optical Instrumentation Engineers, Bellingham, WA, ETATS-UNIS  (1981) (Revue)
SPIE, Bellingham, Wash., ETATS-UNIS  (2008) (Monographie)

Mots-clés anglais / English Keywords

Optical properties

;

Plasmonics

;

Nanostructures

;

Temperature effects

;

Hydroxides

;

Magnetite

;

Iron oxide

;

Ferromagnetic fluid

;

Transition element compounds

;

Inorganic compounds

;

Nanoparticles

;

Random distribution

;

Time dependence

;

Magnetic field effects

;

Precipitation

;

Optical anisotropy

;

Relaxation

;

Light scattering

;

Mots-clés français / French Keywords

4225F

;

4290

;

0130C

;

Fe2O3

;

Fe3O4

;

Propriété optique

;

Plasmonique

;

Nanostructure

;

Effet température

;

Hydroxyde

;

Magnétite

;

Oxyde de fer

;

Fluide ferromagnétique

;

Composé de métal de transition

;

Composé minéral

;

Nanoparticule

;

Distribution aléatoire

;

Dépendance temps

;

Effet champ magnétique

;

Précipitation

;

Anisotropie optique

;

Relaxation

;

Diffusion lumière

;

Mots-clés espagnols / Spanish Keywords

Hierro óxido

;

Fluido ferromagnético

;

Distribución aleatoria

;

Localisation / Location

INIST-CNRS, Cote INIST : 21760, 35400017292252.0120

Nº notice refdoc (ud4) : 21188339



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