TY - JOUR
T1 - Thermoelectric properties of the Yb9Mn4.2-xZn xSb9 solid solutions
AU - Ohno, Saneyuki
AU - Zevalkink, Alexandra
AU - Takagiwa, Yoshiki
AU - Bux, Sabah K.
AU - Snyder, G. Jeffrey
N1 - Copyright:
Copyright 2014 Elsevier B.V., All rights reserved.
PY - 2014/5/28
Y1 - 2014/5/28
N2 - Yb9Mn4.2Sb9 has been shown to have extremely low thermal conductivity and a high thermoelectric figure of merit attributed to its complex crystal structure and disordered interstitial sites. Motivated by previous work which shows that isoelectronic substitution of Mn by Zn leads to higher mobility by reducing spin disorder scattering, this study investigates the thermoelectric properties of the solid solution, Yb 9Mn4.2-xZnxSb9 (x = 0, 1, 2, 3 and 4.2). Measurements of the Hall mobility at high temperatures (up to 1000 K) show that the mobility can be increased by more than a factor of 3 by substituting Zn into Mn sites. This increase is explained by the reduction of the valence band effective mass with increasing Zn, leading to a slightly improved thermoelectric quality factor relative to Yb9Mn4.2Sb 9. However, increasing the Zn-content also increases the p-type carrier concentration, leading to metallic behavior with low Seebeck coefficients and high electrical conductivity. Varying the filling of the interstitial site in Yb9Zn4+ySb9 (y = 0.2, 0.3, 0.4 and 0.5) was attempted, but the carrier concentration (∼1021 cm-3 at 300 K) and Seebeck coefficients remained constant, suggesting that the phase width of Yb9Zn4+ySb9 is quite narrow.
AB - Yb9Mn4.2Sb9 has been shown to have extremely low thermal conductivity and a high thermoelectric figure of merit attributed to its complex crystal structure and disordered interstitial sites. Motivated by previous work which shows that isoelectronic substitution of Mn by Zn leads to higher mobility by reducing spin disorder scattering, this study investigates the thermoelectric properties of the solid solution, Yb 9Mn4.2-xZnxSb9 (x = 0, 1, 2, 3 and 4.2). Measurements of the Hall mobility at high temperatures (up to 1000 K) show that the mobility can be increased by more than a factor of 3 by substituting Zn into Mn sites. This increase is explained by the reduction of the valence band effective mass with increasing Zn, leading to a slightly improved thermoelectric quality factor relative to Yb9Mn4.2Sb 9. However, increasing the Zn-content also increases the p-type carrier concentration, leading to metallic behavior with low Seebeck coefficients and high electrical conductivity. Varying the filling of the interstitial site in Yb9Zn4+ySb9 (y = 0.2, 0.3, 0.4 and 0.5) was attempted, but the carrier concentration (∼1021 cm-3 at 300 K) and Seebeck coefficients remained constant, suggesting that the phase width of Yb9Zn4+ySb9 is quite narrow.
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U2 - 10.1039/c4ta00539b
DO - 10.1039/c4ta00539b
M3 - Article
AN - SCOPUS:84899407698
VL - 2
SP - 7478
EP - 7483
JO - Journal of Materials Chemistry A
JF - Journal of Materials Chemistry A
SN - 2050-7488
IS - 20
ER -