a1 Department of Physics, Boston College, Chestnut Hill, Massachusetts 02467
a2 Los Alamos National Laboratory, Los Alamos, New Mexico 87545
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)