DSM : Thesis SL-DSM-14-0484

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Research field

Soft matter and complex fluids / Solid state physics, chemistry and nanosciences
Thermal energy, combustion, flows / Engineering science

Title

Magneto-thermoelectric effect in ferrofluids

Abstract

The application of a temperature difference T across a solid conductor causes mobile charge carriers to diffuse from hot to cold regions, giving rise to a thermoelectric voltage Delta V=-SDelta T. The prefactor S is called the thermopower or Seebeck coefficient and describes how electrical energy can be generated from the thermal energy. The efficiency of a thermoelectric material is given by the ?figure of merit? ZT= (TS^2sigma)/k where sigma and k are electrical conductivity and total thermal conductivity.



In this thesis project, we will study a novel thermoelectric material; namely, ferrofluids - a colloidal suspension of magnetic nanoparticles. The goal of this project is two-fold. First, we will experimentally investigate the hitherto unexplored phenomenon in ferrofluids, i.e., the magneto-thermoelectric effect due to the thermodiffusion of magnetic nanoparticles (electrically charged) under a temperature gradient. Second, we intend to identify new liquid-based thermoelectric material for waste-heat recovery applications.



Our motivation to seek for enhanced thermal-to-electric energy conversion capacity in liquid systems is very straight forward. The thermoelectric effect is proportional to the transport entropy carried by the diffused (charged) particles. Thus, an enhanced thermoelectric effect is expected in electrolytes containing nanoparticles with a high internal degree of freedom. In addition, the application of magnetic field should also influence the movement of magnetic nanoparticles, possibly increasing the fluid's Seebeck coefficient even further. Such an experimental demonstration of magneto-thermoelectric effect in ferrofluids will offer new and original direction in thermoelectric energy materials research using colloidal solutions and magnetic nanoparticles.



The experimental work will involve electrical, thermal and thermoelectrical transport measurements, implementation of automated data acquisition techniques and analysis of the resulting data obtained.

Location

Institut rayonnement et matière de Saclay
Service de Physique de l'Etat Condensé
Systèmes Physiques Hors-équilibre, hYdrodynamique, éNergie et compleXes
Centre : Saclay
Starting date : 01/10/2013

Contact person

SAWAKO NAKAMAE
CEA / DSM/IRAMIS/SPEC/SPHYNX
Bât 772

CEA-Saclay
Phone : 01 69 08 75 38

More about

http://iramis.cea.fr/spec/Phocea/Pisp/index.php?nom=sawako.nakamae
http://iramis.cea.fr/spec/SPHYNX

University / Graduate School

Paris Sud
Physique en Île-de-France - ENS Paris -

Thesis supervisor

SAWAKO NAKAMAE
CEA / DSM/IRAMIS/SPEC/SPHYNX
Bât 772

CEA-Saclay


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