Study of Effect of Interparticle Interactions on the Diffusion Coefficient in Concentrated Magnetic Fluids by Forced Rayleigh Scattering (CAT#: STEM-ST-0064-YJL)

Name: Study of Effect of Interparticle Interactions on the Diffusion Coefficient in Concentrated Magnetic Fluids by Forced Rayleigh Scattering
SKU: STEM-ST-0064-YJL
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Introduction

The magnetic fluids are constituted of maghemite nanoparticles γ-Fe2O3 coated with citrate molecules that ensure them a negative superficial charge. They are dispersed in water at pH 7 with a volume fraction φ ranging from 1% up to 25%. The particle diameters d follow a lognormal distribution characterized here by d0=()=9.8 nm and σ=0.25. The dipolar parameter γ/φ =μ0m2V/KT that quantifies the dipolar interactions between two particles compared to thermal energy, is 32 for this ferrofluid.

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Principle Applications Procedure Materials

Principle

Forced Rayleigh scattering (FRS) is a light scattering technique used to investigate light-induced grating structures that decay in a relaxational or almost relaxational manner. Such gratings can be created by interference and absorption of two pump beams and probed by a third beam, usually of different frequency. They may consist of spatially varying excited state populations with picosecond lifetimes or of long-lived variations in temperature, composition, and/or density. Forced Rayleigh scattering provides high sensitivity with respect to the amplitude and dynamics of such gratings and allows investigations not accessible by classical scattering techniques.