Article Unexpected p-type thermoelectric transport arising from magnetic Mn substitution in Fe2V1−xMn x Al Heusler compounds

Rajveer Jha ORCID (National Institute for Materials Science) ; Naohito Tsujii SAMURAI ORCID (National Institute for Materials Science) ; Fabian Garmroudi ; Sergii Khmelevskyi ; Ernst Bauer ; Takao Mori SAMURAI ORCID (National Institute for Materials Science)

Journal of Materials Chemistry C-Unexpected p-type thermoelectric transport arising from magnetic Mn substitution in Fe2V1-xMnxAl Heusler compounds.pdf
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Rajveer Jha, Naohito Tsujii, Fabian Garmroudi, Sergii Khmelevskyi, Ernst Bauer, Takao Mori. Unexpected p-type thermoelectric transport arising from magnetic Mn substitution in Fe2V1−xMn x Al Heusler compounds. Journal of Materials Chemistry C. 2024, 12 (24), 8861-8872. https://doi.org/10.1039/d4tc00779d
SAMURAI

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(abstract)

P-type Fe2VAl-based thermoelectrics have been much less investigated compared to their respective n-type counterparts. Thus, it is crucial to identify novel doping strategies to realize enhanced p-type Fe2VAl Heusler compounds. In the current study, the effect of Mn substitution in Fe2V1-xMnxAl is investigated with respect to temperature-dependent electronic transport as well as temperature- and field-dependent magnetic properties. We find an anomalous and unexpected p-type Seebeck coefficient for nominally n-doped Fe2V1-xMnxAl over an extremely large range of concentrations up to x=0.6. Using density functional theory (DFT) calculations, this is traced back to distinct modifications of the electronic structure, i.e., localized magnetic defect states (m=2.43 μB) at the valence and conduction band edges, and a concomitant pinning of the Fermi level within the pseudogap. Furthermore, we were able to further optimize the thermoelectric properties by co-doping Al antisites in off-stoichiometric Fe2V0.9Mn0.1Al1+y, yielding sizeable values of the power factor, PF = 2.2 mWK-2m-1 in Fe2V0.9Mn0.1Al1.1 at 350 K, and figure of merit, ZT~ 0.1 for highly off-stoichiometric Fe2V0.9Mn0.1Al1.5 at T = 500 K. Our work underlines the prospect of engineering Fe2VAl-based Heusler compounds via magnetic doping to realize enhanced p-type thermoelectris and encourages studies involving other types of co-substitution for Mn-substituted Fe2V1-xMnxAl.

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Keyword: thermoelectric

Date published: 2024-05-23

Publisher: Royal Society of Chemistry (RSC)

Journal:

  • Journal of Materials Chemistry C (ISSN: 20507526) vol. 12 issue. 24 p. 8861-8872

Funding:

  • JST-Mirai Program JPMJMI19A1
  • Japan Society for the Promotion of Science 22H01761

Manuscript type: Publisher's version (Version of record)

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First published URL: https://doi.org/10.1039/d4tc00779d

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Updated at: 2024-10-07 14:41:51 +0900

Published on MDR: 2024-10-07 14:41:51 +0900

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