Magnetic and electrical properties of Fe2+xV1−xAl

Electrical and Magnetic Properties of Selected Fe-Based High Entropy Alloys

“…The plots of lnρ versus 1/T (ρ resistivity, T temperature) for the data in the temperature interval 150300 K (the temperature range depends on the sample) becomes almost linear, and an energy gap ∆ of about 110 meV is tentatively obtained for samples: 2-am, 1-ms and 2-ms, assuming that they are semiconducting. The obtained values of the energy gap are the same as estimated by Okulov et al [23], but signicantly smaller (by one order) than ones obtained for Heusler-type alloys [19,20,24,25]. The small values of ∆ suggest that the densities of states of the investigated samples exhibit a pseudo-gap rather than a real energy gap.…”

Characteristics of a granular electronic system in Heusler-type Fe2+xV1−xAl

“…Consequently, it is possible that substituted systems, such as Fe 2+x V 1−x Al and Fe 2 VAl 1−δ , follow M t = Z t − 24 and are half-metallic below T C while M t = 0 at Z t = 24 for stoichiometric Fe 2 VAl and Fe 2 VGa. As shown in figure 7, the saturation moments M s of Fe 2+x V 1−x Al [11,17,23], Fe 2 VAl 1−δ [20], and Fe 2 V 1−x Cr x Al [24] follow M t = Z t − 24 in the range 24 < Z t < 25. The compositions of Fe 2+x V 1−x Al examined in this study fall into this range, and, plausibly, conduction electrons located at the Fermi level consist mainly of the 3d-electron band [25].…”

Thermoelectric performance and the role of anti-site disorder in the 24-electron Heusler TiFe2Sn

“…[23,22] The Seebeck coefficient is consistently positive, revealing that holes are the dominant carrier for all TiFe 2 Sn samples. These results separate TiFe 2 Sn from Heusler compound VFe 2 Al, which has a Seebeck coefficient that is highly sensitive to atomic ratio: pure VFe 2 Al has a maximum Seebeck coefficient near 30 µVK −1 , and variations in stoichiometry, such as varying the V:Al [18] or V:Fe [17] ratio, or doping the Al site with Ge [15] can enhance it to 80 µVK −1 or −120 µVK −1 . Figure 8 illustrates the effects on thermoelectric properties resulting from the substitution of Sn for Sb in the form TiFe 2 Sn 1−y Sb y (y = 0.01, 0.05).…”

“…[11] These predictions are aligned with what is known for the wellstudied Heusler compound VFe 2 Al that has been of interest since the discovery of unusual temperature dependence of electrical resistivity [12] attributed to a pseudogap at the Fermi level. [13,14] VFe 2 Al displays a large Seebeck coefficient (|S| > 150 µV/K) upon varying the VEC slightly from 24, achieved by introducing Ge [15] or Si [16] to the Al site, varying the V-Al ratio, [17,18,19] and varying the Fe-V ratio. [20,21] In contrast to VFe 2 Al, TiFe 2 Sn is a less explored compound, and the existing literature on TiFe 2 Sn has not indicated significant improvements in Seebeck coefficient upon varying the Ti:Fe ratio.…”