New materials with surprising superconductive properties

High-entropic materials are extremely hard and resistant to corrosion and high temperatures, which makes them ideal for applications in extreme conditions. Researchers from the Institute of Experimental Physics SAS in Košice, together with colleagues from the Montanuniversität Leoben in Austria, have succeeded in preparing high-entropic alloys in the form of thin films.

“The excellent mechanical properties of these alloys are commonly used for surface treatment machining tools, and surfaces where high hardness and corrosion resistance are required. Our research has shown that these materials also exhibit the phenomenon of superconductivity, which surprised us quite a bit given their significant internal disorder,” said Gabriel Pristáš from the Institute of Experimental Physics SAS.

Experimental physicists from the Slovak Academy of Sciences, together with their colleagues from Austria, have succeeded in significantly improving the superconducting properties of thin films by using nitrogen doping, which led to increase of the transition temperature to the superconducting state by up to eightfold. They were able to observe this phenomenon only because they precisely increased the nitrogen doping and found the optimal concentration for the maximum increase in the transition temperature.

“The usual procedure of nitrogen doping to the maximum concentration in the case of high-entropic alloys does not mean a maximum increase in the transition temperature, and therefore it can easily happen that a significant improvement in superconducting properties is overlooked in such a case. Using several unique experimental techniques that are well established in our workplace, we managed not only to discover this phenomenon, but also to explain the physical nature of the improvement in superconducting properties,” added the experimental physicist.

The discovery of the scientists from Institute of Experimental Physics SAS opens up the possibility of using this method also for high-entropic alloys with different compositions. Potential areas of application of these materials are electrodes for supercapacitors, elements for quantum devices, or their current use in the construction of single-photon detectors.

 

Results were published in these papers:

[1] G. Pristáš, J. Bačkai, M. Orendáč, S. Gabáni, F. Košuth, M. Kuzmiak, P. Szabó, E. Gažo, R. Franz, S. Hirn, G. C. Gruber, C. Mitterer, S. Vorobiov, K. Flachbart: “Superconductivity in medium- and high-entropy alloy thin films: impact of thickness and external pressure”, Physical Review B 107 (2023), 024505.

[2] Gabriel Pristáš, Georg C. Gruber, Matúš Orendáč, Július Bačkai, Jozef Kačmarčík, Filip Košuth, Slavomír Gabáni, Pavol Szabó, Christian Mitterer, Karol Flachbart: “Multiple transitiion temperature enhancement in superconducting TiNbMoTaW high entropy alloy films through tailored N incorporation”, Acta Materialia 262 (2024) 119428

 

Contact: Gabriel Pristáš, +421 908 689 287, email: gabriel.pristas@saske.sk

Source: SAS News
See also: Veda na dosah