Emergence of asymmetric skew-scattering dominated anomalous Nernst effect in the spin gapless semiconductors Co_1+xFe_1-xCrGa

Journal Article · Tue Oct 18 00:00:00 EDT 2022 · Physical Review. B

DOI:https://doi.org/10.1103/physrevb.106.134416· OSTI ID:2419224

Chanda, A. ^[1]; Rani, Deepika ^[2]; Nag, Jadupati ^[3]; Alam, Aftab ^[3]; Suresh, K. G. ^[3]; Phan, M. H. ^[4]; Srikanth, H. ^[4]

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1. Univ. of South Florida, Tampa, FL (United States); OSTI
2. Indian Inst. of Technology (IIT), Mumbai (India). Magnetic Materials Laboratory; Indian Inst. of Technology (IIT), New Delhi (India)
3. Indian Inst. of Technology (IIT), Mumbai (India). Magnetic Materials Laboratory
4. Univ. of South Florida, Tampa, FL (United States)

Heusler alloy-based spin gapless semiconductors (SGSs) with very high Curie temperatures $\left(T_C\right)$ have recently gained enormous attention because of their unconventional electronic structures. They exhibit a nonzero band gap in one of the spin channels and a zero band gap in the other spin channel, making them an important class of materials for tunable spin transport. Here, we report the experimental observation of anomalous Nernst effect (ANE) in ${\mathrm{Co}}_{1+x}{\mathrm{Fe}}_{1-x}\mathrm{CrGa}$ ( $x=0$ , 0.2, 0.4, and 0.5), which are the emerging quaternary Heusler alloy-based SGSs. While the electron-electron elastic scattering and the disorder-mediated weak localization effect play the major roles in electrical transport for all the samples at low temperatures, the magnon-drag effect was found to dominate the longitudinal thermoelectric transport. The ANE coefficient at room temperature increases from $\approx 0.018\mu \mathrm{V}{\mathrm{K}}^{-1}$ for $x=0$ to $\approx 0.063\mu \mathrm{V}{\mathrm{K}}^{-1}$ for $x=0.5$ , which is higher than that for ${\mathrm{Ni}}_{81}{\mathrm{Fe}}_{19}$ and compressively strained $\mathrm{SrRu}{\mathrm{O}}_3$ films. Our analysis indicates that the observed ANE in these samples originates from asymmetric skew scattering of charge carriers.

• Research Organization: Univ. of South Florida, Tampa, FL (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES)
• Grant/Contract Number: FG02-07ER46438
• OSTI ID: 2419224
• Journal Information: Physical Review. B, Journal Name: Physical Review. B Journal Issue: 13 Vol. 106; ISSN 2469-9950; ISSN PRBMDO
• Publisher: American Physical Society (APS)
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
Half-metals
Materials Science
Nernst effect
Physics
Spin caloritronics
Thermomagnetic effects
Thermopower