For the first time, the quantitative texture analysis of edge free sintered Bi 2 Te 2.4 Se 0.6 samples elaborated by high-energy ball milling and Spark Plasma Texturing is performed. As expected, due to the structural anisotropy, the forging process results in a significant decrease in electrical resistivity perpendicularly to the uniaxial stress field. Surprisingly, this also leads to a large decrease in the lattice thermal conductivity in this direction. Crystallite boundaries amorphization as evidenced by transmission electron microscopy explains this latter decrease due to the friction induced by the applied pressure and grains sliding on each other during reorientation. X-ray diffraction also evidences development of strong crystallite size anisotropy and more isotropic microstrain developments under pressure, simultaneously favoring electronic conduction and phonon scattering, respectively. The thermoelectric performance is thus increased, however, the quantitative texture analysis demonstrates that the enhanced texture is only slightly responsible for the improved performance that rather comes from a peculiarly engineered microstructure.
2038
This is an author's version published in: http://oatao.univ-toulouse.fr/24435In recent decades, thermoelectricity has been widely studied as a potential new source of renewable energy. One of the major challenges to improve the efficiency of thermoelectric (TE) devices is to minimize the contact resistance between the active material and the electrodes, since this represents the major loss of charge in a TE module. This article describes the fabrication of an apparatus for TE leg characterization built with commercial and custom-made parts based on the analog one-dimensional transmission-line method. This device permits contact resistance measurements of bulk TE legs. p-and n-type TE materials, Mg 2 Si 0.98 Bi 0.02 and MnSi 1.75 Ge 0.02 , respectively, were metallized with nickel foils and used as test materials for contact resistance characterization. Contact resistance values of 0.5 mX mm 2 for Ni/Mg 2 Si 0.98 Bi 0.02 junctions and 4 mX mm 2 for Ni/MnSi 1.75 Ge 0.02 junctions have been measured. Contact resistance measurements are discussed depending on materials processing and the experimental measurement conditions.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.