1. Cavendish Laboratory and the Interdisciplinary Research Centre for Superconductivity, University of Cambridge, Cambridge CB3 0HE, UK
2. Present address: Department of Materials Science, University of Cambridge, Cambridge CB2 3QZ, UK (N.D.M.) MPI Chemische Physik fester Stoffe, Bayreuther Str. 40, 01187 Dresden, Germany (F.M.G.).

Correspondence to: G. G. Lonzarich¹ Correspondence should be addressed to G.G.L.

Abstract

In a conventional superconductor, the binding of electrons into the paired states that collectively carry the supercurrent is mediated by phonons — vibrations of the crystal lattice. Here we argue that, in the case of the heavy fermion superconductors CePd₂Si₂ and CeIn₃, the charge carriers are bound together in pairs by magnetic spin–spin interactions. The existence of magnetically mediated superconductivity in these compounds could help shed light on the question of whether magnetic interactions are relevant for describing the superconducting and normal-state properties of other strongly correlated electron systems, perhaps including the high-temperature copper oxide superconductors.