Balancing Scattering Channels: A Panoscopic Approach toward Zero Temperature Coefficient of Resistance Using High‐Entropy Alloys

Abstract

global positioning system (GPS) devices. [2] Moreover, to further improve sensitivity and for use in controlled heating applications (e.g., in furnaces) by resistance heating, a high electrical resistivity (ρ) is desired. [1,3,4] Designing novel materials with little or no change in ρ over a very wide range of temperatures, however, remains a big challenge, which is indicated by the fact that more than a century after their discovery, Constantan (Cu-Ni) and Manganin (Cu-Mn-Ni) based alloys are still the most widely used materials in these contexts. [1,3,4] A crucial material parameter for the abovementioned applications is the temperature coefficient of resistance (TCR), Δρ/ρ 0 ΔT, which measures the variation of the electrical resistivity within a certain temperature range where ρ 0 , Δρ (= ρ − ρ 0 ) and ΔT (= T − T 0 ) are the resistivity at the lower temperature (typically the resistivity near 0 K, unless stated otherwise), difference in resistivity between the higher and the lower temperatures, and the temperature difference between the high and low temperatures, respectively. [5,6] Metals commonly display positive TCR values, which originate from an increasing probability of electrons to experience thermally induced scattering events. For simple metals, phonons represent the dominating scattering channel already at ambient temperatures exhibiting a linear temperature dependence for T > T D /3, where T D is the Debye temperature. [7,8] At very low temperatures, on the other hand, the resistivity is dominated by scattering from impurities and defects giving rise to the socalled residual resistivity, ρ 0 . In this work we will refer to the resistivity obtained at the lowest measurement temperature ≈2-5 K as the residual resistivity, ρ 0 . For the Manganin reference, we use the ρ 0 and ρ 300K that are obtained by fitting (cf. the Supporting Information). [9] Moreover, in metals with magnetic impurities, scattering from magnons (spin-waves) can reach significant levels at low temperatures. [10] In specific cases, where magnetic atoms are embedded in nonmagnetic host metals, the Kondo effect (temperature dependent scattering of conduction electrons by magnetic impurities at low temperatures) can play a dominant role at temperatures near zero Kelvin. [9] The origin of sign and magnitude of the TCR is still a subject of debate. [5][6][7][8]11] In the 1960s, Ioffe and Regel defined the minimum mean-free path (l min ) of the charge carrier to be ≈a (i.e., the interatomic spacing). [7,8,12] This limit, commonly known as Designing alloys with an accurate temperature-independent electrical response over a wide temperature range, specifically a low temperature coefficient of resistance (TCR), remains a big challenge from a material design point of view. More than a century after their discovery, Constantan (Cu-Ni) and Manganin (Cu-Mn-Ni) alloys remain the top choice for strain gauge applications and high-quality resistors up to 473-573 K. Here, an average TCR is demonstrated that is up to ≈800 times smaller in the tempera...

Complicated magnetic structure and its strong correlation with the anomalous Hall effect in Mn3Sn

“…To obtain the Hall conductivity, the temperature evolution of ρxx is measured at B = 0 and B = 1T, respectively (Fig.5(c)).The metallic behavior of Mn3Sn is exhibited by the ρxx-T curves, and the magnetoresistance (MR) at 1T is very small (approximately -2.3%). Due to the low electron-phonon scattering in Mn3Sn,[22] the longitudinal resistivity almost remains constant at T > 300 K, which is the near-zero temperature coefficient of resistivity (NZ-TCR).The reason for the large AHE in a noncollinear AFM is still unclear. The theoretical predictions from Li et al suggest that the nonvanishing Berry curvature arising from the noncollinear AFM is responsible for the observed large AHE [13].…”

Recent Advances on High‐Entropy Alloys for 3D Printing

“…[36] Due to such characteristics, PBF and DED have been widely utilized in various applications within the aerospace, energy, biomedical, automotive, marine and offshore, molding and tooling industries. [37] High-entropy alloys (HEAs), emerging as a novel frontier in the metal materials community, [38][39][40][41][42][43] have high mixing configurational entropies that tend to stabilize solid solutions based on simple underlying face-centered cubic (FCC), body-centered cubic (BCC) or hexagonal close-packed (HCP) structures. [44][45][46][47] In general, the definition of an HEA is based on composition or entropy.…”

“…[51] Through screening proper combinations of their constituent elements and regulating their proportions, HEAs can exhibit remarkable mechanical properties at high temperatures and exceptional strength, ductility and fracture toughness at cryogenic temperatures, as well as superparamagnetism, superconductivity and exceptional irradiation resistance. [43,[52][53][54][55][56][57] Therefore, they are considered alternatives for high-temperature turbine blades, hightemperature molds and dies, hard coatings on cutting tools, components of 4 th generation nuclear reactors, etc. [58] Compared to conventional manufacturing processes, DED and PBF hold greater promise for the development of HEA products.…”

Strategic Optimization of the Electronic Transport Properties of Pseudo‐Ternary Clathrates

“…[41] In this context, the addition of a third framework species could provide entropic stabilization, which is the basic principle behind high-entropy alloys. [42][43][44] Given these considerations, here, we present a systematic computational study of the thermoelectric PF as a function of composition in Ba 8 Al x Ga y Ge 46−x−y and Ba 8 Ga x Ge y Si 46−x−y in relation to the cost of these compounds. This is accomplished via a combination of density functional theory (DFT) calculations, Monte Carlo (MC) simulations based on cluster expansion (CE) models and Boltzmann transport theory (BTT) calculations.…”