Details

Autor(en) / Beteiligte

• Kohen, A.
• Noat, Y.
• Proslier, T.
• Lacaze, E.
• Aprili, M.
• Sacks, W.
• Roditchev, D.

Titel

Fabrication and characterization of scanning tunneling microscopy superconducting Nb tips having highly enhanced critical fields

Ist Teil von

• Physica. C, Superconductivity, 2005-02, Vol.419 (1), p.18-24

Ort / Verlag

Amsterdam: Elsevier B.V

Erscheinungsjahr

2005

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• We report a simple method for the fabrication of Niobium superconducting (SC) tips for scanning tunneling microscopy which allow atomic resolution. The tips, formed in situ by the mechanical breaking of a niobium wire, reveal a clear SC gap of 1.5 meV and a critical temperature T c = 9.2 ± 0.3 K, as deduced from Superconductor Insulator Normal metal (SIN) and Superconductor Insulator Superconductor (SIS) spectra. These match the values of bulk Nb samples. We systematically find an enhanced value of the critical magnetic field in which superconductivity in the tip is destroyed (around 1 T for some tips) up to five times larger than the critical field of bulk Nb (0.21 T). Such enhancement is attributed to a size effect at the tip apex.