Effect of Nanostructuring on the Thermoelectric Properties of β-FeSi<sub>2</sub>
Linda Abbassi,
David Mesguich,
David Berthebaud,
Sylvain Le Tonquesse,
Bhuvanesh Srinivasan,
Takao Mori,
Loïc Coulomb,
Geoffroy Chevallier,
Claude Estournès,
Emmanuel Flahaut,
Romain Viennois,
Mickaël Beaudhuin
Affiliations
Linda Abbassi
ICGM, Univ. Montpellier, CNRS, ENSCM, Montpellier, France
David Mesguich
CIRIMAT, CNRS, Université de Toulouse, 118 Route de Narbonne, CEDEX 9, 31062 Toulouse, France
David Berthebaud
CNRS-Saint Gobain-NIMS, IRL 3629, Laboratory for Innovative Key Materials and Structures (LINK), National Institute for Materials Science (NIMS), Tsukuba 305-0044, Japan
Sylvain Le Tonquesse
CNRS-Saint Gobain-NIMS, IRL 3629, Laboratory for Innovative Key Materials and Structures (LINK), National Institute for Materials Science (NIMS), Tsukuba 305-0044, Japan
Bhuvanesh Srinivasan
CNRS-Saint Gobain-NIMS, IRL 3629, Laboratory for Innovative Key Materials and Structures (LINK), National Institute for Materials Science (NIMS), Tsukuba 305-0044, Japan
Takao Mori
MANA, National Institute for Materials Science (NIMS), 1-1-1 Namiki, Tsukuba 305-0044, Japan
Loïc Coulomb
ICGM, Univ. Montpellier, CNRS, ENSCM, Montpellier, France
Geoffroy Chevallier
CIRIMAT, CNRS, Université de Toulouse, 118 Route de Narbonne, CEDEX 9, 31062 Toulouse, France
Claude Estournès
CIRIMAT, CNRS, Université de Toulouse, 118 Route de Narbonne, CEDEX 9, 31062 Toulouse, France
Emmanuel Flahaut
CIRIMAT, CNRS, Université de Toulouse, 118 Route de Narbonne, CEDEX 9, 31062 Toulouse, France
Romain Viennois
ICGM, Univ. Montpellier, CNRS, ENSCM, Montpellier, France
Mickaël Beaudhuin
ICGM, Univ. Montpellier, CNRS, ENSCM, Montpellier, France
Nanostructured β-FeSi2 and β-Fe0.95Co0.05Si2 specimens with a relative density of up to 95% were synthesized by combining a top-down approach and spark plasma sintering. The thermoelectric properties of a 50 nm crystallite size β-FeSi2 sample were compared to those of an annealed one, and for the former a strong decrease in lattice thermal conductivity and an upshift of the maximum Seebeck’s coefficient were shown, resulting in an improvement of the figure of merit by a factor of 1.7 at 670 K. For β-Fe0.95Co0.05Si2, one observes that the figure of merit is increased by a factor of 1.2 at 723 K between long time annealed and nanostructured samples mainly due to an increase in the phonon scattering and an increase in the point defects. This results in both a decrease in the thermal conductivity to 3.95 W/mK at 330 K and an increase in the power factor to 0.63 mW/mK2 at 723 K.
