Structural and physical properties of Mg{sub 3-x}Zn{sub x}Sb{sub 2} (x=0-1.34)

Journal Article · Sat Sep 15 00:00:00 EDT 2007 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2007.06.011· OSTI ID:21043823

Ahmadpour, Faraz ^[1]; Kolodiazhnyi, Taras ^[2]; Mozharivskyj, Yurij ^[1]

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1. Department of Chemistry, McMaster University, 1280 Main Street West, Hamilton, Ontario, L8S 4M1 (Canada)
2. National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan)

The Mg{sub 3-x}Zn{sub x}Sb{sub 2} phases with x=0-1.34 were prepared by direct reactions of the elements in tantalum tubes. According to the X-ray single crystal and powder diffraction, the Mg{sub 3-x}Zn{sub x}Sb{sub 2} phases crystallize in the same P3-bar m1 space group as the parent Mg{sub 3}Sb{sub 2} phase. The Mg{sub 3-x}Zn{sub x}Sb{sub 2} structure is different from the other substituted structures of Mg{sub 3}Sb{sub 2}, such as (Ca, Sr, Ba) Mg{sub 2}Sb{sub 2} or Mg{sub 5.23}Sm{sub 0.77}Sb{sub 4}, in a way that in Mg{sub 3-x}Zn{sub x}Sb{sub 2} the Mg atoms on the tetrahedral sites are replaced, while in the other structures Mg on the octahedral sites is replaced. Thermoelectric performance for the two members of the series, Mg{sub 3}Sb{sub 2} and Mg{sub 2.36}Zn{sub 0.64}Sb{sub 2}, was evaluated from low to room temperatures through resistivity, Seebeck coefficient and thermal conductivity measurements. In contrast to Mg{sub 3}Sb{sub 2} which is a semiconductor, Mg{sub 2.36}Zn{sub 0.64}Sb{sub 2} is metallic and exhibits an 18-times larger dimensionless figure-of-merit, ZT, at room temperature. However, thermoelectric performance of Mg{sub 2.36}Zn{sub 0.64}Sb{sub 2} is still poor and it is mostly due to its large electrical resistivity. - Graphical abstract: The Mg atoms in Mg{sub 3}Sb{sub 2} were successfully substituted with Zn, with Zn going exclusively into the tetrahedral sites. Zn substitution increases the electrical conductivity in Mg{sub 2.36}Zn{sub 0.64}Sb{sub 2} by closing the band gap. This change combined with a decrease in the thermal conductivity improves the ZT value.

• OSTI ID: 21043823
• Journal Information: Journal of Solid State Chemistry, Vol. 180, Issue 9; Other Information: DOI: 10.1016/j.jssc.2007.06.011; PII: S0022-4596(07)00244-7; Copyright (c) 2007 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0022-4596
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ANTIMONIDES
DIRECT REACTIONS
ELECTRIC CONDUCTIVITY
MAGNESIUM COMPOUNDS
SEMICONDUCTOR MATERIALS
SPACE GROUPS
TANTALUM
TEMPERATURE RANGE 0273-0400 K
THERMAL CONDUCTIVITY
THERMOELECTRIC PROPERTIES
TRIGONAL LATTICES
TUBES
X-RAY DIFFRACTION
ZINC COMPOUNDS