High critical current density and high-tolerance superconductivity in high-entropy alloy thin films

Abstract

High-entropy alloy (HEA) superconductors—a new class of functional materials—can be utilized stably under extreme conditions, such as in space environments, owing to their high mechanical hardness and excellent irradiation tolerance. However, the feasibility of practical applications of HEA superconductors has not yet been demonstrated because the critical current density (Jc) for HEA superconductors has not yet been adequately characterized. Here, we report the fabrication of high-quality superconducting (SC) thin films of Ta–Nb–Hf–Zr–Ti HEAs via a pulsed laser deposition. The thin films exhibit a large Jc of >1 MA cm−2 at 4.2 K and are therefore favorable for SC devices as well as large-scale applications. In addition, they show extremely robust superconductivity to irradiation-induced disorder controlled by the dose of Kr-ion irradiation. The superconductivity of the HEA films is more than 1000 times more resistant to displacement damage than that of other promising superconductors with technological applications, such as MgB2, Nb3Sn, Fe-based superconductors, and high-Tc cuprate superconductors. These results demonstrate that HEA superconductors have considerable potential for use under extreme conditions, such as in aerospace applications, nuclear fusion reactors, and high-field SC magnets.

Discovery of robust superconductivity against volume shrinkage

“…御大变形超导体" [70][71][72][73][74][75] . (-ΔV/V 0 = 21.6%) for the (TaNb) 0.67 (HfZrTi) 0.33 superconductor, and 120 GPa (-ΔV/V 0 = 34.7%) for the NbTi superconductor, while P C is 1 bar for the elemental Ta and Nb superconductors.…”

Optimization of Laser-Wavelength Dependence for Open-Air Atmospheric Pressure Pulsed Laser Deposition of AlCrFeMnTi High-Entropy Alloy for Tailored Surface Properties

“…15 Due to the myriad advantages of the PLD technique for the deposition of thin films, the technique has been employed for the fabrication of high-entropy materials in several different applications. Guo 18 Laser deposition in open air at atmospheric pressure is a low-cost and facile method of thin-film fabrication because as opposed to the conventional PLD technique, there is no requirement for the use of a vacuum chamber. 19 Open-air PLD has been employed in the fabrication of porous metal oxide films, such as nanoporous TiO 2 and ZnO.…”

“…Laszlo et al studied the mechanical properties of pulsed laser-deposited AlCoCrFeNi x HEAs and nitrides and also explored the biocorrosion behavior of the thin-film alloys in simulated body fluid . In another work, Jung et al employed PLD for the fabrication of superconductive thin films of TaNbHfZrTi HEA on c-cut Al 2 O 3 substrates over a wide range of temperatures . Laser deposition in open air at atmospheric pressure is a low-cost and facile method of thin-film fabrication because as opposed to the conventional PLD technique, there is no requirement for the use of a vacuum chamber .…”

“… 17 In another work, Jung et al employed PLD for the fabrication of superconductive thin films of TaNbHfZrTi HEA on c-cut Al 2 O 3 substrates over a wide range of temperatures. 18 Laser deposition in open air at atmospheric pressure is a low-cost and facile method of thin-film fabrication because as opposed to the conventional PLD technique, there is no requirement for the use of a vacuum chamber. 19 Open-air PLD has been employed in the fabrication of porous metal oxide films, such as nanoporous TiO 2 and ZnO.…”

Low-Frequency Conductivity of Low Wear High-Entropy Alloys

“…Previous research on HEAs has predominantly focused on their outstanding mechanical properties, while investigations into their electrical characteristics remain limited. Apart from their unique low-temperature superconducting properties 5 , one of the most signi cant electrical features observed in the literature for HEAs is their temperatureindependent conductivity 6 . Additionally, the direct-current (DC) conductivity of HEAs is generally orders of magnitude higher than that of pure metals or low-entropy alloys.…”