The discovery in 1996 of superconductivity at 0.2K near a magnetic quantum phase transition in CeIn3 opened a new dynasty of superconducting heavy electron materials, with many peculiar parallels to cuprate superconductors. In 2000, the introduction of additional layers of XIn 2 , led to the discovery of the so-called "115" superconductors, with a tenfold increase in Tc. By 2002, the replacement of Ce by Pu, drove the Tc up by an additional order of magnitude to 18.5K. The recent discovery of a second material in this family has further deepened the mystery.
In this talk I'll discuss the two newest "high temperature" heavy fermion superconductors in this series: PuCoGa5 and NpPd 2 Al 5 . These materials radically challenge the way we think about strongly correlated superconductivity. The way these materials directly transition from Curie paramagnets into anisotropic superconductors suggests a central role of spin as a driver for heavy electron superconductors - not just as the pairing glue - but as the basic fabric of the condensate.
Motivated by these new materials, I'll discuss a model for superconductivity in the highest temperature superconductors in which the superconducting condensate involves formation of composite pairs between spins and conduction electrons. Using this idea, we'll discuss how the physics of superconductivity and the Kondo effect can be combined, giving rise to a composite pairing model for the new superconductors.
 H. Hegger, C. Petrovic, E. G. Moshopoulou, M. F. Hundley, J. L. Sarrao, Z. Fisk, and J. D. Thompson, ''Pressure-Induced Superconductivity in Quasi-2D CeRhIn 5 '' Phys. Rev. Lett. 84 , 4986-4989 (2000).
 J. L. Sarrao et al. , “Plutonium-based superconductivity with a transition temperature above 18 K", Nature (London) 420 , 297-299 (2002).
 Rebecca Flint, M. Dzero, P. Coleman, "Heavy electrons and the symplectic symmetry of spin", Nature Physics 4 , 643 - 648 (2008).