Superconductivity was first observed in solid mercury at a temperature of 4.19 Kelvin in 1911, not long after liquid helium was first produced in 1908.
The 1980's discoveries were of the first "high temperature" superconductors (where "high temperature" means "above the boiling point of liquid nitrogen").
Liquid nitrogen is much easier to deal with than liquid helium.
The 1980's discoveries were of the first "high temperature" superconductors (where "high temperature" means "above the boiling point of liquid nitrogen").
Liquid nitrogen is much easier to deal with than liquid helium.