Electron Tunneling into Superconducting Filaments: Depth Profiling The Energy GAP of NbTi Filaments from Magnet Wires

摘要: Squeezable electron tunneling (SET) junctions consisting of superconducting NbTi filaments (extracted from magnet wires) and sputtered Nb thin-film counter electrodes were used to determine the energy gap at surface filaments. The current versus voltage curves immersed in liquid helium 4 K measured for a series taken same wire. Each filament had been etched remove layer varying thickness so that could be determined as function depth into an “average” filament. It was found some manufacturing processes yield having layers with reduced gaps 0.4 meV compared interior bulk values ranging 1.2 1.3 meV.