Magnesium Diboride

In March 2001, Jun Akimitsu and colleagues at Aoyama-Gakuin University in Tokyo, Japan reported a superconducting transition temperature of 39 Kelvin for magnesium diboride. This has generated a great deal of excitement not only because this is the highest transition temperature yet observed for a type-II superconductor, but also because the materials used are quite common.

There will be a great deal of interest in whether the material can be used to form wires. If its mechanical properties can be managed, it could contribute significantly to making superconducting magnets. Sergey L. Bud'ko and colleagues at Iowa State University have formed wires from the material. They observed the isotope effect in this superconductor, suggesting that it follows the behavior of other conventional superconductors. The isotope effect is a signature of interaction with the crystal lattice via phonons, and is an indication that the superconductor may act according to the BCS theory of superconductivity.

All of this is preliminary information. Part of it was drawn from:
"Run-of-the-mill compound becomes superstar" by P. Weiss, Science News 159, p134 (Mar 3, 2001)

Superconducting Plutonium

The plutonium compound PuCoGa₅ has been found to be superconducting with a critical temperature of about 18 K. Gregory Stewart of the University of Florida and John Sarrao and colleagues at the Los Alamos National Laboratory reported this unexpected superconductor in the journal Nature.