Enhanced thermoelectric properties of samarium boride
| Autor: | Alif Sussardi, T. Tanaka, L. Schlapbach, A. Ullah Khan, Takao Mori |
|---|---|
| Rok vydání: | 2015 |
| Předmět: |
Materials science
Samarium boride Condensed matter physics Magnetic moment Thermoelectric Boride Fermi level Metals and Alloys chemistry.chemical_element Mixed valency High temperature Thermoelectric materials Surfaces Coatings and Films Electronic Optical and Magnetic Materials Samarium chemistry.chemical_compound symbols.namesake chemistry Electrical resistivity and conductivity Thermoelectric effect symbols Figure of merit |
| Zdroj: | Journal of Materiomics. 1(3):196-204 |
| ISSN: | 2352-8478 |
| DOI: | 10.1016/j.jmat.2015.07.007 |
| Popis: | SmB62 single crystals were successfully grown by the floating zone (FZ) method. The high-temperature thermoelectric properties were investigated, together with magnetic properties and specific heat at low-temperature. The electrical resistivity, ρ, shows variable-range-hopping (VRH) behavior with significantly lower values than other rare-earth RB62 (RB66) compounds. An effective magnetic moment, μeff, of 0.42 μB/Sm was estimated, which if straightforwardly taken indicates a mixed valency for SmB62 with Sm2+:Sm3+ = 1:1, which is the first ever indicated for RB66-type compounds. Localization length of the VRH at the Fermi level, ξ, was estimated to be 3.33 A indicating that carriers in SmB62 are much less localized than in YB66 which has 0.56 A. The thermoelectric behavior of SmB62 is striking, with ρ reduced by two orders of magnitude while maintaining large Seebeck coefficients, and as a result the power factor is ∼30 times higher than other rare-earth phases. Overall the figure of merit ZT amounts to ∼0.13 at 1050 K, with an extrapolated value of ∼0.4 at 1500 K, an expected working temperature for topping cycles in thermal power plants; that gives a ∼40 times enhancement for Sm. Since there are few thermoelectric materials applicable for very-high temperature applications, this discovery gives new interest in the samarium higher borides. |
| Databáze: | OpenAIRE |
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