Superconducting properties of Nb${}_{0.85}$Sc${}_{0.15}$ film deposited by magnetron co-sputtering

Abstract

The technology has been developed for synthesizing Nb${}_{1-x}$Sc${}_x$ films using magnetron co-sputtering from Nb and Sc targets. The material synthesis was accompanied by structural characterization using X-ray diffraction and X-ray reflectometry methods, which enabled the determination of thickness, phase composition and crystal structure. We also analyzed the superconducting properties. The critical temperature $T_c$ was measured for samples with different concentarions of Sc and Nb. The maximum value of $T_c$ equal to 6.35 K was observed for sample with a scandium content of approximately 15 %, which was determined by Auger spectroscopy. Transport and magnetoresistive measurements were performed in microbridges with length of 50 $\mu$m, width of 2 $\mu$m, and thickness of 30 nm. The critical current density was as high as 2.5 ${\text{ MA/cm}}^2$. Magnetic measurements were performed with the field oriented perpendicular to the sample. The upper critical field $H_{c2}(0)=3.2$ T, electron diffusion coefficient $D=1.1$ ${\text{cm}}^2/s$, and coherence length ${\xi }_{GL}=10.1$ nm. The synthesized Nb${}_{1-x}$Sc${}_x$ intermetallic compound shows promise for various functional cryogenic electronics devices. \keywords{NbSc; superconductor; microbridge}

10 pages, 8 figures, 2 tables