aLaboratorium für Festkörperphysik, ETH Zürich, 8093 Zürich, Switzerland Received 29 May 2006; revised 29 May 2006; accepted 17 July 2006. Available online 30 January 2007.
PuCoGa5 with 18.5 K has an extremely high Tc for superconductivity compared with other actinide materials having Tcs around 2–3 K. It appears to be a “high Tc superconductor” in the field of actinides. After nearly 20 years of research in high Tc superconductors only Cu containing materials have Tcs above about 30 K (exception MgB2). BCS theory cannot explain such high transition temperatures, thus other or additional coupling mechanisms, like magnetic exchange are necessary. Mixed valence, spin holes in an antiferromagnetic lattice, small energy difference between the various valences and two-dimensionality are common features of Cu and Pu containing superconductors. It can be shown in this paper that the mechanism for superconductivity is the same for Cu and Pu containing materials.