| Autor: |
Morozova, Natalia V., Ovsyannikov, Sergey V., Korobeinikov, Igor V., Karkin, Alexander E., Ken-ichi Takarabe, Yoshihisa Mori, Shigeyuki Nakamura, Shchennikov, Vladimir V. |
| Předmět: |
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| Zdroj: |
Journal of Applied Physics; 2014, Vol. 115 Issue 21, p213705-1-213705-9, 9p, 1 Diagram, 5 Graphs |
| Abstrakt: |
We report results of investigations of electronic transport properties and lattice dynamics of Al-doped magnesium silicide (Mg2Si) thermoelectrics at ambient and high pressures to and beyond 15 GPa. High-quality samples of Mg2Si doped with 1 at.% of Al were prepared by spark plasma sintering technique. The samples were extensively examined at ambient pressure conditions by X-ray diffraction studies, Raman spectroscopy, electrical resistivity, magnetoresistance, Hall effect, thermoelectric power (Seebeck effect), and thermal conductivity. A Kondo-like feature in the electrical resistivity curves at low temperatures indicates a possible magnetism in the samples. The absolute values of the thermopower and electrical resistivity, and Raman spectra intensity of Mg2Si:Al dramatically diminished upon room-temperature compression. The calculated thermoelectric power factor of Mg2Si:Al raised with pressure to 2-3 GPa peaking in the maximum the values as high as about 8 ×10-3 W/(K²m) and then gradually decreased with further compression. Raman spectroscopy studies indicated the crossovers near ~5-7 and ~11-12 GPa that are likely related to phase transitions. The data gathered suggest that Mg2Si:Al is metallized under moderate pressures between ~5 and 12 GPa. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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