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We report the effect of Ir doping on the anomalous Hall effect (AHE) and anomalous Nernst effect (ANE) in Fe3Co single-crystal thin films. (Fe3Co)100–xIrx (x ≤ 12%) composition-spread thin films are fabricated on MgO(100) substrates by a combinatorial sputtering technique for a high-throughput and systematic characterization. From a structural analysis using X-ray diffraction, the films are grown epitaxially on the substrates and B2-ordered phase is detected from x = 7.3% to 12%. The compositional dependence of the AHE, magnetoresistance, ANE, and Seebeck effect is measured to obtain anomalous Hall resistivity (ρ_yx^A), longitudinal resistivity (ρ_xx), anomalous Nernst coefficient (S_ANE), and Seebeck coefficient (S_SE), respectively. From these transport measurements, we calculate anomalous Nernst conductivity (α_xy^A). A large enhancement of the ρ_yx^A value is observed upon Ir doping by a factor of ≈ 9.2 for x = 12% at 300 K. By employing a scaling analysis to the AHE results, extrinsic contribution is found to be increased after Ir doping in the low-Ir concentration regime, while intrinsic contribution becomes more dominant in the high-Ir concentration regime. On the other hand, unlike the ρ_yx^A, the S_ANE does not show significant compositional dependence. We find that AHE-related contribution is dominant to the S_ANE compared to the contribution from direct conversion of a temperature gradient to a transverse charge current by anomalous Nernst conductivity. We also find that the α_xy^A value sharply changes from a positive to negative value immediately after Ir doping, showing a negative maximum at x ≈ 1%, followed by a decrease in magnitude to almost zero for x = 12%. Based on the Mott’s relation and the scaling analysis of the AHE, we suggest a possible connection between the α_xy^A and the extrinsic contribution of the AHE. These experimental results and analysis will provide insights into the relationship between the AHE and ANE in ferromagnetic alloys upon heavy metal doping.

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• In Copyright
  

  ©2024 American Physical Society

Keyword: anomalous Hall effect, anomalous Nernst effect, Seebeck effect, spin-orbit coupling

Date published: 2024-02-12

Publisher: American Physical Society (APS)

Journal:

• Physical Review B (ISSN: 24699969) vol. 109 issue. 5 054415

Funding:

• Japan Science and Technology Corporation JPMJCR21O1
• Japan Science and Technology Corporation JPMJER2201
• Ministry of Education, Culture, Sports, Science and Technology JPMXP1122715503
• Japan Society for the Promotion of Science JP21H01608
• Japan Society for the Promotion of Science JP22K20494

Manuscript type: Author's version (Accepted manuscript)

MDR DOI: https://doi.org/10.48505/nims.4715

First published URL: https://doi.org/10.1103/physrevb.109.054415

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Updated at: 2024-08-31 08:31:07 +0900

Published on MDR: 2024-08-31 08:31:07 +0900