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Ternary MIn2S4 (M = Mn,Fe, Co,Ni) Thiospinels – Crystal Structure and Thermoelectric Properties |
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| Authors: | Paweł Wyżga Igor Veremchuk Matej Bobnar Christoph Hennig Andreas Leithe-Jasper Roman Gumeniuk |
| Institution: | 1. Institut für Experimentelle Physik, TU Bergakademie Freiberg, Leipziger Straße 23, 09599 Freiberg, Germany
Max-Planck-Institut für Chemische Physik fester Stoffe, Nöthnitzer Straße 40, 01187 Dresden, Germany;2. Max-Planck-Institut für Chemische Physik fester Stoffe, Nöthnitzer Straße 40, 01187 Dresden, Germany;3. Helmholtz-Zentrum Dresden-Rossendorf Institute of Resource Ecology, Bautzner Landstraße 400, 01314 Dresden, Germany Rossendorf Beamline (BM20-CRG), European Synchrotron Radiation Facility, 6 rue Jules Horowitz, 38043 Grenoble, France;4. Institut für Experimentelle Physik, TU Bergakademie Freiberg, Leipziger Straße 23, 09599 Freiberg, Germany |
| Abstract: | A combined structural, magnetic and thermoelectric study of polycrystalline ternary MIn2S4 (M = Mn, Fe, Co, Ni) thiospinels is presented. All compounds crystallize with MgAl2O4-type structure. Rietveld refinement analysis confirmed that the preferred crystallographic position of transition metal element changes from mainly tetrahedral 8a for Mn to exclusively octahedral 16d for Ni (i.e. increase of the inversion parameter). Magnetic susceptibility measurements revealed M-elements to possess 2+ oxidation state in MIn2S4. All these compounds order antiferromagnetically with Néel temperatures TN ranging from 5–13 K. The studied thiospinels are n-type semiconductors with large values of electrical resistivity ρ > 0.6 Ω · m at room temperature. An increase of the inversion parameter leads to a reduction of the determined activation energies, as well as to a more disorder-like behavior of thermal conductivity. The highest thermoelectric Figure of merit ZT was observed for MIn2S4 with M = Fe, Ni, which adopt inverse spinel structure. |
| Keywords: | Solid-phase synthesis Spinel phases Sulfur X-ray diffraction Thermoelectric |