Signatures of Surface Magnetic Disorder in Niobium Films

• Published in: IEEE transactions on applied superconductivity Vol. 31; no. 5; pp. 1 - 5
• Main Authors: Samsonova, A.S., Zolotov, P.I., Baeva, E.M., Lomakin, A.I., Titova, N.A., Kardakova, Anna I., Goltsman, G.N.
• Format: Journal Article
• Language: English
• Published: New York IEEE 01-08-2021; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Abrikosov-Gorkov model; Low level; Magnetic moments; Magnetism; Niobium; Resistance; Scattering; Substrates; Superconducting magnets; superconducting thin films; Superconducting transition temperature; Superconductivity; Temperature dependence; Temperature measurement; Thickness; Thin films
• ISSN: 1051-8223; 1558-2515
• DOI: 10.1109/TASC.2021.3065281

We present our studies on the evolution of the normal and superconducting properties with thickness of thin Nb films with a low level of non-magnetic disorder (<inline-formula><tex-math notation="LaTeX">k_Fl\approx 150</tex-math></inline-formula> for the thickest film in the set). The analysis of the superconducting behavior points to the presence of magnetic moments, hidden in the native oxide on the surface of Nb films. Using the Abrikosov-Gorkov theory, we obtain the density of surface magnetic moments of <inline-formula><tex-math notation="LaTeX">10^{13}</tex-math></inline-formula> cm<inline-formula><tex-math notation="LaTeX">^{-2}</tex-math></inline-formula>, which is in agreement with the previously reported data for Nb films.