On the structure and electronic properties of Fe2V0.8W0.2Al thin films

Alleno, É.; Berche, Alexandre; Crivello, Jean-Claude; Diack-Rasselio, A.; Jund, Philippe

doi:10.1039/d0cp03738a

Cited by 5 publications

(4 citation statements)

References 25 publications

(30 reference statements)

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“…Then, it was reported that a new alloy model suggested in ref. [10] gives only rise to a Seebeck coefficient S ∼ 30 µV/K at T ∼ 400 K , which is much smaller than the experimental value. How-ever, the actual alloy structures of Fe 2 V 0.8 W 0.2 Al have not been fully explored both theoretically and experimentally.…”

mentioning

confidence: 58%

“…In a previous study, on the basis of the first principles calculation, the origin of this huge Seebeck coefficient was suggested to be a result of the large mobility due to many Weyl points and a large logarithmic energy derivative of the electronic density of states near the Fermi energy [9]. On the other hand, it was also claimed [10] that the crystal structure assumed in ref. [9] is different from the experimental one.…”

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confidence: 97%

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Theory of Huge Thermoelectric Effect Based on Magnon Drag Mechanism: Application to Thin-Film Heusler Alloy

Matsuura,

Ogata,

Mori

et al. 2021

Preprint

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To understand the unexpectedly high thermoelectric performance observed in the thin-film Heusler alloy Fe2V0.8W0.2Al, we study the magnon drag effect, generated by the tungsten based impurity band, as a possible source of this enhancement, in analogy to the phonon drag observed in FeSb2. Assuming that the thin-film Heusler alloy has a conduction band integrating with the impurity band, originated by the tungsten substitution, we derive the electrical conductivity L11 based on the self-consistent t-matrix approximation and the thermoelectric conductivity L12 due to magnon drag, based on the linear response theory, and estimate the temperature dependent electrical resistivity, Seebeck coefficient and power factor. Finally, we compare the theoretical results with the experimental results of the thin-film Heusler alloy to show that the origin of the exceptional thermoelectric properties is likely to be due to the magnon drag related with the tungsten-based impurity band.

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confidence: 58%

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confidence: 97%

Theory of Huge Thermoelectric Effect Based on Magnon Drag Mechanism: Application to Thin-Film Heusler Alloy

Matsuura,

Ogata,

Mori

et al. 2021

Preprint

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“…A recent study reported that the metastable A2 structure, stabilized in Fe 2 V 0.8 W 0.2 Al thin films, could be responsible for the record-high thermoelectric performance measured in these films [30]. On the other hand, bandstructure calculations by Alleno et al have not revealed promising features of the electronic density of states (eDOS) near the Fermi energy E F , which would originate large values of the Seebeck coefficient [44]. Matsuura et al proposed instead a huge magnon drag thermopower in these Heusler alloys as a possible explanation for the observed enhancement [45].…”

Section: Introductionmentioning

confidence: 99%

Unveiling the structure-property relationship in metastable Heusler compounds by systematic disorder tuning

et al. 2023

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Heusler compounds represent a unique class of materials that exhibit a wide range of fascinating and tuneable properties such as exotic magnetic phases, superconductivity, band topology or thermoelectricity. An exceptional, but for Heusler compounds common feature is that they are prone to antisite defects and disorder. In this regard, the Fe2VAl Heusler compound has been a particularly interesting and disputed candidate. Even though, various theoretical scenarios for the interplay of physical properties and disorder have been proposed, the metastable disordered A2 phase hitherto precluded experimental investigation in bulk samples. Here, we report experimental results on disorder-tuned Fe2VAl0.9Si0.1 alloys all the way towards the A2 phase, which we realized via rapidly quenching our samples from high temperatures. We measured the thermoelectric properties of these materials in a wide temperature range (4 to 700 K), which suggest a gradual semimetal/narrow-gap semiconductor → metal transition upon increasing the disorder. We also find a large anomalous Hall effect in the disordered A2 phase, arising from the side-jump scattering of charge carriers at the antisite magnetic moments. This is corroborated by measurements of the temperature-and field-dependent magnetization, which increases dramatically up to ≈ 2.5 µB/f.u. as compared to the ordered compound (< 0.1 µB/f.u.). This study provides the first experimental realization of the metastable A2 structure in bulk Fe2VAl-based alloys and grants insight into the structure -property relationship of these materials. Our work confirms that temperature-induced antisite disorder, occuring during thermal heat treatment, can be a precisely tuneable parameter in the family of Heusler compounds.

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“…6) We should also know that the large ZT = 6 was reported for no other Fe 2 VAl-based samples except for Fe 2 V 0.8 W 0.2 Al, and the bulk samples of the same composition did not possess such a large value of ZT even for the samples reported by the same group. 5,6) Although, based on the experimental observations, the Fe 2 VAl-based Heusler alloy thin-film sample was reported to possess such a large value of ZT, Alleno et al 7) ruled out the possibility of that high thermoelectric performance from the computational point of view. More recently, Matsuura et al 8) concluded that the magnon drag mechanism could contribute to such very high ZT.…”

Section: Introductionmentioning

confidence: 99%

Thermoelectric performance of Fe₂V_0.9W_0.1Al thin films deposited on n-type Si substrates

Machda

Singh²,

Kuga

et al. 2023

Jpn. J. Appl. Phys.

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Fe2V0.9W0.1Al thin films are prepared on n-type Si substrates by means of radio-frequency magnetron sputtering with varied substrate temperatures from 743 – 1043 K, then subsequently annealed for one hour in vacuum at 1043 K. The thin films deposited at 1043 K are chemically degraded, exhibiting a low Seebeck coefficient, –65 µVK–1, at 330 K. On the other hand, the films deposited at 943 K possess –100 µVK–1 in Seebeck coefficient at around 330 – 350 K, which is very similar to the Seebeck coefficient of the bulk W-substituted Fe2VAl that possesses well-ordered L21 structure. The maximum power factor of 1.6 mWm–1K–2 was obtained for the sample deposited at 943 K. Accordingly, with the thermal conductivity of 3.5 Wm-1K-1, the figure of merit reached up to ZT = 0.16, which is comparable with Fe2V0.9W0.1Al of bulks and two times larger than that of the thin films of Si-substituted Fe2VAl.

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On the structure and electronic properties of Fe₂V_0.8W_0.2Al thin films

Abstract: A very large thermoelectric figure of merit ZT = 6 at 380 K has recently been reported in Fe2V0.8W0.2Al under thin-film form (Ref. 1, Hinterleitner et al., Nature 576 (2019)...

Cited by 5 publications

References 25 publications

Theory of Huge Thermoelectric Effect Based on Magnon Drag Mechanism: Application to Thin-Film Heusler Alloy

Theory of Huge Thermoelectric Effect Based on Magnon Drag Mechanism: Application to Thin-Film Heusler Alloy

Unveiling the structure-property relationship in metastable Heusler compounds by systematic disorder tuning

Thermoelectric performance of Fe₂V_0.9W_0.1Al thin films deposited on n-type Si substrates

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On the structure and electronic properties of Fe2V0.8W0.2Al thin films

Abstract: A very large thermoelectric figure of merit ZT = 6 at 380 K has recently been reported in Fe2V0.8W0.2Al under thin-film form (Ref. 1, Hinterleitner et al., Nature 576 (2019)...

Cited by 5 publications

References 25 publications

Theory of Huge Thermoelectric Effect Based on Magnon Drag Mechanism: Application to Thin-Film Heusler Alloy

Theory of Huge Thermoelectric Effect Based on Magnon Drag Mechanism: Application to Thin-Film Heusler Alloy

Unveiling the structure-property relationship in metastable Heusler compounds by systematic disorder tuning

Thermoelectric performance of Fe2V0.9W0.1Al thin films deposited on n-type Si substrates

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On the structure and electronic properties of Fe₂V_0.8W_0.2Al thin films

Thermoelectric performance of Fe₂V_0.9W_0.1Al thin films deposited on n-type Si substrates