Publication: Structural evolution from neutron powder diffraction of nanostructured snte obtained by arc melting
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2023-01
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Abstract
Among chalcogenide thermoelectric materials, SnTe is an excellent candidate for intermediate temperature applications, in replacement of toxic PbTe. We have prepared pure polycrystalline SnTe by arc melting, and investigated the structural evolution by temperature-dependent neutron powder diffraction (NPD) from room temperature up to 973 K. In this temperature range, the sample is cubic (space group Fm-3m) and shows considerably larger displacement parameters for Te than for Sn. The structural analysis allowed the determination of the Debye model parameters and provided information on the Sn-Te chemical bonds. SEM images show a conspicuous nanostructuration in layers below 30 nm thick, which contributes to the reduction of the thermal conductivity down to 2.5 W/m center dot K at 800 K. The SPS treatment seems to reduce the number of Sn vacancies, thus diminishing the carrier density and increasing the Seebeck coefficient, which reaches 60 mu V K^(-1) at 700 K, as well as the weighted mobility, almost doubled compared with that of the as-grown sample.
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© 2022 by the authors. Licensee MDPI
This research was funded by the Ministerio de Ciencia e Innovacion (MCIN/AEI/10.13039/501100011033) through grant numbers PID2021-122477OB-I00 and TED2021-129254B-C22, by the Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior-Brazil (CAPES) under grant number 88887.603800/2021-00, and by the Fundacao de Amparo a Pesquisa do Estado do Rio Grande do Sul (FAPERGS) (21/2551-0000695-1).