[neuah]

In this version, in figure 6a and b the new log scale of the IV curve looks quite linear and increasing in the range of 150 to 250 mA. I thought that it should be flat if it was a superconductor (no resistance). Can anyone explain how that behavior still supports it being a superconductor?

[willis936]

Because you're not measuring a pure superconductor sample. To be able to observe the cliff on the IV curve you need enough of the current path in between the electrodes to be superconducting, but certainly not all of it will be. This is true even in commercial superconductors, just with the ohmic losses pushed down even further.

[neuah]

Ah that makes sense. Thanks!