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Regular version of the site

Article

Superconductivity in epitaxial TiN films points to surface magnetic disorder

Physical Review Applied. 2019. Vol. 12. P. 054001-1-054001-10.
Saveskul N. A., Titova N., Baeva E., Semenov A. V., Lubenchenko A. V., Saha S., Reddy H., Bogdanov S., Marinero E. E., Shalaev V., Boltasseva A., Khrapai V., Kardakova A. K., Goltsman G.

We analyze the evolution of the normal and superconducting properties of epitaxial TiN films, characterized by high Ioffe-Regel parameter values, as a function of the film thickness. As the film thickness decreases, we observe an increase of the residual resistivity, that becomes dominated by diffusive surface scattering for d≤20nm. At the same time, a substantial thickness-dependent reduction of the superconducting critical temperature is observed compared to the bulk TiN value. In such high-quality material films, this effect can be explained by a weak magnetic disorder residing in the surface layer with a characteristic magnetic defect density of approximately 10^12cm^−2. Our results suggest that surface magnetic disorder is generally present in oxidized TiN films