Video 1. Superconductor, 4-probe measurement by Frederiksen Scientific A/S (2015) Source. OK experiment, illustrates the educational kit they sell. No temperature control, just dumps liquid nitrogen into conductor and watches it drop. But not too bad either. The kit sale link is broken (obviously, enterprise stuff), but there are no archives unfortunately. But it must be some High-temperature superconductor
Ciro Santilli