Semiconductors

Influence of spark plasma sintering parameters on the thermoelectric properties of $n$-type Mg$_3$Sb$_2$-Mg$_3$Bi$_2$ solid solution materials

A. A. Mikhailova^ab, K. A. Scherbakova^ab, E. V. Argunov^a, A. A. Markin^b, A. R. Akhmadeev^b, V. A. Dybov^b, M. V. Ananyev^c, N. Yu. Tabachkova<sup>a

a</sup> National University of Science and Technology «MISIS», Moscow
^b JSC "Giredmet" SRC RF, the Federal State Research and Design Institute of Rare Metal Industry, Moscow
^c School of Chemical Engineering, University of Birmingham, United Kingdom

Abstract: Samples based on the Mg$_3$Sb$_2$-Mg$_3$Bi$_2$ solid solution were obtained by mechanochemical synthesis followed by spark plasma sintering. The regularities of the influence of compaction process parameters on the electrical and thermal physical properties of the samples were identified. It was established that the application of a two-stage heating regime promotes an increase in electrical conductivity up to 325 S/cm at 390 K, while simultaneously ensuring a reduction in lattice thermal conductivity to 0.49 W/(m $\Omega$ K). Collectively, these changes enable achieving a maximum thermoelectric figure of merit $zT$ of 1.38 at 732 K.

Keywords: thermoelectric materials, Zintl phases, Seebeck coefficient, electrical conductivity, thermal conductivity.

Received: 28.05.2025
Revised: 03.09.2025
Accepted: 22.09.2025

DOI: 10.61011/FTT.2025.09.61614.149-25

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