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Description
Heusler alloys are a unique class of materials which enable the option to change their physical properties by simple adjustment of the alloy's chemical composition. It was shown in different studies, that changes in chemical composition can lead to tuning of the observed phenomenon, and its enhancement. Well-known Heusler ferromagnetic superconductor Ni$_2$NbSn has a critical temperature of 3 K and Curie temperature of around 13 K. Mainly the value of critical temperature makes the material difficult to study and does not support its practical application.
In the presented work, the influence of chemical doping of Ni$_2$NbSn using Ga, Ge, and Sb elements was investigated. The most crucial parameters were evaluated, such as superconducting transition temperature, and also Curie temperature. The chemical tuning of the mother alloy was performed with 1$\%$ and 2$\%$ doping. It was found that doping may in some cases suppress the superconducting or ferromagnetic properties in the material, but on the other hand, favourable enhancement of superconducting temperature has been observed for 1$\%$ Sb doping, up to 6.42 K. The resistance measurements revealed the background of the coexistence of ferromagnetism and superconductivity can be different than in the case of other chemical doping.
Acknowledgements
This work was supported by the projects APVV-16-0079, Slovak VEGA grant. No. 1/0180/23, 1/0404/21, 2/0058/20. University Science Park TECHNICOM for Innovation Applications Supported by Knowledge Technology– II- Phase, ITMS: 313011D232., supported by the Research \& Development Operational Programme funded by the ERDF.
References
[1] S. Nalevanko, J. Kačmarčík, L. Galdun, et. al., “Ni$_2$NbSn Heusler ferromagnetic superconductor: Magneto-structural and transport characterisation,” Intermetallics, vol. 167, no. 108231, Feb. 2024. doi: 10.1016/j.intermet.2024.108231.
[2] A. Reigle, K. Mason, J. Slattery, et. al., “Superconducting properties of in doped ZrNi$_2$Ga$_{1−x}$In$_x$, ” Solid State Commun, vol. 291, pp. 28–31, Jan 2019. doi: 10.1016/j.ssc.2019.01.015.
