TY - JOUR
T1 - Thermoelectric Properties of Variants of Cu4Mn2Te4 with Spinel-Related Structure
AU - Guo, Quansheng
AU - Vaney, Jean Baptiste
AU - Virtudazo, Raymond
AU - Minami, Ryunosuke
AU - Michiue, Yuichi
AU - Yamabe-Mitarai, Yoko
AU - Mori, Takao
N1 - Funding Information:
This research was supported by JST CREST Grant Number JPMJCR15Q6, Japan. Support from JSPS KAKENHI Grant Number JP16H06441 is also acknowledged. J.B.V. is supported by a JSPS fellowship. We thank Mr. S. Takenouchi for performing ICP.
Publisher Copyright:
© 2018 American Chemical Society.
PY - 2018/5/7
Y1 - 2018/5/7
N2 - Thermoelectric properties of Cu4Mn2Te4, which is antiferromagnetic with a Néel temperature TN = 50 K and crystallizes in a spinel-related structure, have been investigated comprehensively here. The phase transition occurring at temperatures 463 and 723 K is studied by high-temperature X-ray diffraction (XRD) and differential scanning calorimetry (DSC), and its effect on thermoelectric properties is examined. Hypothetically Cu4Mn2Te4 is semiconducting according to the formula (Cu+)4(Mn2+)2(Te2-)4, while experimentally it shows p-type metallic conduction behavior, exhibiting electrical conductivity σ = 2500 Ω-1 cm-1 and Seebeck coefficient α = 20 μV K-1 at 325 K. Herein, we show that the carrier concentration and thus the thermoelectric transport properties could be further optimized through adding electron donors such as excess Mn. Discussions are made on the physical parameters contributing to the low thermal conductivity, including Debye temperature, speed of sound, and the Grüneisen parameter. As a result of simultaneously boosted power factor and reduced thermal conductivity, a moderately high zT = 0.65 at 680 K is obtained in an excess Mn\In co-added sample, amounting to 5 times that of the pristine Cu4Mn2Te4. This value (zT = 0.65) is the best result ever reported for spinel and spinel-related chalcogenides.
AB - Thermoelectric properties of Cu4Mn2Te4, which is antiferromagnetic with a Néel temperature TN = 50 K and crystallizes in a spinel-related structure, have been investigated comprehensively here. The phase transition occurring at temperatures 463 and 723 K is studied by high-temperature X-ray diffraction (XRD) and differential scanning calorimetry (DSC), and its effect on thermoelectric properties is examined. Hypothetically Cu4Mn2Te4 is semiconducting according to the formula (Cu+)4(Mn2+)2(Te2-)4, while experimentally it shows p-type metallic conduction behavior, exhibiting electrical conductivity σ = 2500 Ω-1 cm-1 and Seebeck coefficient α = 20 μV K-1 at 325 K. Herein, we show that the carrier concentration and thus the thermoelectric transport properties could be further optimized through adding electron donors such as excess Mn. Discussions are made on the physical parameters contributing to the low thermal conductivity, including Debye temperature, speed of sound, and the Grüneisen parameter. As a result of simultaneously boosted power factor and reduced thermal conductivity, a moderately high zT = 0.65 at 680 K is obtained in an excess Mn\In co-added sample, amounting to 5 times that of the pristine Cu4Mn2Te4. This value (zT = 0.65) is the best result ever reported for spinel and spinel-related chalcogenides.
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U2 - 10.1021/acs.inorgchem.8b00301
DO - 10.1021/acs.inorgchem.8b00301
M3 - Article
C2 - 29630370
AN - SCOPUS:85046622340
VL - 57
SP - 5258
EP - 5266
JO - Inorganic Chemistry
JF - Inorganic Chemistry
SN - 0020-1669
IS - 9
ER -