MRS Communications

Research Letters

Phonon drag effect in nanocomposite FeSb2

Mani Pokharela1 c1, Huaizhou Zhaoa1, Kevin Lukasa1, Zhifeng Rena1, Cyril Opeila1 and Bogdan Mihailaa2

a1 Department of Physics, Boston College, Chestnut Hill, Massachusetts 02467

a2 Los Alamos National Laboratory, Los Alamos, New Mexico 87545

Abstract

We study the temperature dependence of thermoelectric transport properties of four FeSb2 nanocomposite samples with different grain sizes. The comparison of the single crystals and nanocomposites of varying grain sizes indicates the presence of substantial phonon drag effects in this system contributing to a large Seebeck coefficient at low temperature. As the grain size decreases, the increased phonon scattering at the grain boundaries leads to a suppression of the phonon-drag effect, resulting in a much smaller peak value of the Seebeck coefficient in the nanostructured bulk materials. As a consequence, the ZT values are not improved significantly even though the thermal conductivity is drastically reduced.

(Received November 15 2012)

(Accepted February 01 2013)

Correspondence

c1 Address all correspondence to Mani Pokharel at pokharem@bc.edu

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