Fig. 3: Resistance data and localization of Cooper pairs.
From: Superconducting insulators and localization of Cooper pairs
a Resistance versus temperature R(T) measured for five Ti nanowires of length L = 20 μm, thickness d ≃ 35 nm, and nominal width values w indicated in brackets for each of the samples. Solid lines represent fits of the data for samples Ti1 and Ti2 to the theory9 within its validity range. Resistance saturation observed in these two samples at low T is due to finite voltage sensitivity of about few nV corresponding to residual resistance ~100 Ω measured using ac bias current ~10 pA rms. Error bars are smaller than data points. b Localization of Cooper pairs (with charge 2e) generated by quantum tunneling of magnetic fluxons Φ0 across the nanowire. This phenomenon explains the low-temperature behavior of R(T) observed in samples Ti3, Ti4, and Ti5.
