Higher Temperature Superconductors

The latest news of high relevance IMO is this surprising report: Pressure-induced high-temperature superconductivity retained at ambient which pressurised FeSe (Iron Selenide) and then returned it to ambient pressure by a new process which maintained a higher Tc of 37 K. Iron Selenide usually manages about 9 K, so it’s a surprising enhancement maintained at normal pressure. If this process can be replicated and repeated for other superconducting compounds, well here’s some critical temperatures to ponder…

Superconductivity to 262 kelvin via catalyzed hydrogenation of yttrium at high pressures
Critical temperature of 262 K at 182 GPa, with an Upper magnetic field of 103 tesla.

Experimental observation of superconductivity at 215 K in calcium superhydride under high pressures CaH6 with a Tc maximum at 172 GPa.

Room-Temperature Superconductivity in Boron-Nitrogen Doped Lanthanum Superhydride Tc of 290 K at 240 GPa.

The implications for technology are worth pondering. If we can maintain high magnetic field densities at reasonable temperatures, then fusion reactors become immensely easier to build. For example MIT’s ARC Fusion reactor design is half the size of the immense ITER design, because its peak magnetic field is 23 tesla (ITER’s is 11.8 tesla on coil). How much smaller can a reactor be with a 100 tesla on-coil peak field using conductors operating at 100 to 150 K?