Superconductor operates in magnetic fields above 500 kG Available to Purchase

A compound of lead, molybdenum and sulfur, $Pb1.0Mo5.1S6,$ has remained superconducting in a 510‐kilogauss magnetic field at liquid‐helium temperature, 4.2 K. This is the highest upper critical field $Hc2$ (4.2 K) yet reported for a superconductor, and the predicted value for $Hc2$ (0) is 600 kG. Materials that remain superconducting at high magnetic fields could be formed into powerful, lightweight magnets if they can support high current density and are sufficiently strong to withstand the resulting forces. Simon Foner, Edward J. McNiff Jr and Edwin Alexander of the Francis Bitter National Magnet Laboratory, Massachusetts Institute of Technology, described the high‐field measurements at the recent Applied Superconductivity Conference in Oak Brook, Illinois (30 September–2 October) and in the 23 September issue of Physics Letters.