Document Type

Article

Publication Date

11-6-2008

Publication Title

Physical Review E

Abstract

We report an experimental investigation of time dependent anisotropic light scattering by an aqueous suspension of tetramethyl ammonium hydroxide coated Fe3O4 nanoparticles (∼6nm) under the ON-OFF transient of an external dc magnetic field. The study employs the synchronized recording and measurement of the two magnetic-field-induced light-scattering patterns produced by two identical orthogonal He-Ne laser beams passing through the ferrofluid sample and propagating parallel and perpendicular to the applied field, respectively. From these patterns, we extract the time dependence of the induced optical anisotropy, which provides a measure of the characteristic time scale and kinematic response for field-induced structure formation in the sample. We propose that the time evolution of the scattering patterns, which is very fast at short times and significantly slower at long times, can be explained using a model based on a two-stage chain formation and coarsening processes.

Volume

78

Issue

5

First Page

051502-1

Last Page

051502-9

DOI

10.1103/PhysRevE.78.051502

ISSN

1539-3755 (print) 1550-2376 (web)

Rights Statement

©2008 American Physical Society, posted with permission.

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