Superconductiviy in high-entropy alloys

High-entropy alloys (HELs) represent a relatively new class of materials that have attracted considerable attention due to their excellent mechanical and electronic properties. HEA are alloys or compounds that consist of several components (usually 4 or more) with an atomic fraction between 5 and 35%. They are characterized by a high degree of disorder (high configurational entropy) due to the random arrangement of constituents in the crystallographic sites. Recently, high-quality HEA thin films have been successfully prepared, where superconducting properties were investigated. HEA thin films have a high application potential in electronic circuits and devices under extreme conditions. Our intention is to prepare nitride HEA thin films, in order to improve their superconducting properties. Nitriding of superconductors brought significant improvement in superconducting properties such as an increase the value of the transition temperature to the superconducting state. Thin layers of NbN are used in the construction of a single-photon detector, which is used for secure quantum communication. The goal of the doctoral study will be the preparation of nitrided HEA thin films and their characterization as well as measurement of superconducting properties such as critical temperature and upper critical field. In addition, the effect of pressure and thickness will be investigated. The student will be guided through the preparation and characterization of samples, experimental research, data analysis and the presentation of the achieved results.