Superconductivity Behavior in Epitaxial TiN Films Points to Surface Magnetic Disorder
/ Authors
N. A. Saveskul, N. Titova, E. M. Baeva, A. Semenov, A. Lubenchenko, S. Saha, H. Reddy, S. Bogdanov, E. Marinero, V. Shalaev
and 4 more authors
/ Abstract
We analyze the evolution of the normal and superconducting electronic properties in 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 in the residual resistivity, which becomes dominated by diffusive surface scattering for $d\leq20\,$nm. At the same time, a substantial thickness-dependent reduction of the superconducting critical temperature is observed compared to the bulk TiN value. In such a 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 $\sim10^{12}\,\mathrm{cm}^{-2}$. Our results suggest that surface magnetic disorder is generally present in oxidized TiN films.
Journal: Physical Review Applied