TY - JOUR
T1 - Thermoelectric Hexagonal A-Mg-Si with A = Sr and Ba Zintl Phases
AU - Kajitani, T.
AU - Takahashi, K.
AU - Saito, M.
AU - Suzuki, H.
AU - Kikuchi, S.
AU - Kubouchi, M.
AU - Hayashi, K.
N1 - Funding Information:
The present work was partly supported by the Small and Medium Enterprise Agency (the Japanese Ministry of Economy, Trade and Industry) under the contract No. 20140221-Tohoku-18. The band calculation by the use of Wien2k code was done by the cooperation of Prof. Hiroki Tsuchiura, affiliated to the Department of Applied Physics, Tohoku University.
Publisher Copyright:
© 2016, The Minerals, Metals & Materials Society.
PY - 2016/10/1
Y1 - 2016/10/1
N2 - Hexagonal A-Mg-Si with A = Sr and Ba Zintl phases are promising candidates for p-type magnesium silicides usable with n-Mg2Si under 900 K. We synthesized p-type A-Mg-Si Zintl phases by the spark plasma synthesis procedure. Mg2Si and Mg2A powders were mixed at the ratio of 1−x/x with x = 0.3–0.4. Two-step synthesis was performed at 850 K for 20 min and 1100 K for 20 min under uniaxial pressure at 30 MPa. Sintered pellets exhibited a stable p-type thermoelectric property. These pellets consisted of several unknown phases. We found two semiconductor phases, namely A2Mg4Si3 and A2Mg12Si7. The crystal structures of the 2/4/3- and 2/12/7-phases were P6 ¯ 2 m (No. 189)- and P6 3/ m (No. 176)-types, respectively. Sr0.70Mg2Si, Ba3Mg10Si7 and Sr3Mg10Si7 phases are newly found and characterized by a single crystal diffraction study. Previously found Sr2Mg4Si3 single phase polycrystalline 30φ × 10 mm pellets were successfully synthesized. The thermoelectric performance of the Sr2Mg4Si3 single phase sample was tested. The pellets exhibit p-type behavior from room temperature to 700 K. The thermal conductivity, κ, was almost constant at 1.1 W/mK from 350 K to 700 K.
AB - Hexagonal A-Mg-Si with A = Sr and Ba Zintl phases are promising candidates for p-type magnesium silicides usable with n-Mg2Si under 900 K. We synthesized p-type A-Mg-Si Zintl phases by the spark plasma synthesis procedure. Mg2Si and Mg2A powders were mixed at the ratio of 1−x/x with x = 0.3–0.4. Two-step synthesis was performed at 850 K for 20 min and 1100 K for 20 min under uniaxial pressure at 30 MPa. Sintered pellets exhibited a stable p-type thermoelectric property. These pellets consisted of several unknown phases. We found two semiconductor phases, namely A2Mg4Si3 and A2Mg12Si7. The crystal structures of the 2/4/3- and 2/12/7-phases were P6 ¯ 2 m (No. 189)- and P6 3/ m (No. 176)-types, respectively. Sr0.70Mg2Si, Ba3Mg10Si7 and Sr3Mg10Si7 phases are newly found and characterized by a single crystal diffraction study. Previously found Sr2Mg4Si3 single phase polycrystalline 30φ × 10 mm pellets were successfully synthesized. The thermoelectric performance of the Sr2Mg4Si3 single phase sample was tested. The pellets exhibit p-type behavior from room temperature to 700 K. The thermal conductivity, κ, was almost constant at 1.1 W/mK from 350 K to 700 K.
KW - Alkaline earth metal
KW - p-type magnesium silicon semiconductor
KW - structure refinement
KW - Zintl phase
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U2 - 10.1007/s11664-016-4658-3
DO - 10.1007/s11664-016-4658-3
M3 - Article
AN - SCOPUS:84984639508
SN - 0361-5235
VL - 45
SP - 5238
EP - 5245
JO - Journal of Electronic Materials
JF - Journal of Electronic Materials
IS - 10
ER -