Number 429 (Story #3), May 20, 1999 by Phillip F. Schewe and Ben Stein|
SUPERCONDUCTIVITY GOES PLATINUM. It is ironic that some of the best insulators (e.g., perovskite ceramics) should make the best superconductors while some of the best conductors (the noble metals gold, silver, and copper) should be bad superconductors. Indeed the electron-phonon interactions that bring about low-temperature superconductivity is so weak in these metals that they have never been seen to superconduct. Recently, though, physicists at the University of Bayreuth (Reinhard Koenig, 011-49-921-55-3340, firstname.lastname@example.org) in Germany have overcome the recalcitrance of one of those metals, platinum, which became superconducting only at milli-kelvin temperatures. The platinum was studied in the form of a compacted powder which contained only very few magnetic impurities (magnetism being detrimental to superconductivity). Furthermore, it has a much larger surface area, and it is thought that surface vibrations (phonons) may also be important for superconductivity in the platinum powder. This work allows the chance to see how magnetism and superconductivity compete with each other and to study the mechanism of the coupling between superconducting grains of the powder (R. Koenig, A.Schindler, T. Herrmannsdoerfer, Physical Review Letters, 31 May 1999).