5 ms·
The resistance curve stopped at 1e-5 Ω because it has nearly reached the resolution limit of their instrument. Using 4-wire Kelvin sensing, the measurement curr
by segfaultbuserr 3y ago
The resistance curve stopped at 1e-5 Ω because it has nearly reached the resolution limit of their instrument. Using 4-wire Kelvin sensing, the measurement current was 1 mA, the voltage read-out across the material was around 1 to 10 nanovolts - this is around the scale that some of the world's best general-purpose voltmeters can measure down to. The authors assumed that the negligible voltage drop, combined with the abrupt drop and flattening of the resistance vs temperature curve is already a convincing-enough indication of superconductivity.
Hopefully more rigorous testing will be done by one of the teams later.
- lifthrasiir 3y agoWhich is indeed their argument. But in that case they haven't proved that $T_c^{zero}$ = 110 K, they only proved that $T_c^{zero}$ < 110 K. (And I should also note that $T_c^{zero}$ doesn't imply the actual critical temperature $T_c$, while the title strongly suggests so.)
- amelius 3y agoCurious, why didn't they use a larger current for the measurement?
- segfaultbuserr 3y agoWho knows... Too afraid to damage their only sample?