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 CePd 2 Si 2 and CeIn 3 , 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.

No abstract

The magnetic ordering temperature of some rare earth based heavy fermion compounds is strongly pressure-dependent and can be completely suppressed at a critical pressure, pc, making way for novel correlated electron states close to this quantum critical point. We have studied the clean heavy fermion antiferromagnets CePd2Si2 and CeIn3 in a series of resistivity measurements at high pressures up to 3.2 GPa and down to temperatures in the mK region. In both materials, superconductivity appears in a small window of a few tenths of a GPa on either side of pc. We present detailed measurements of the superconducting and magnetic temperature-pressure phase diagram, which indicate that superconductivity in these materials is enhanced, rather than suppressed, by the closeness to magnetic order. 74.20.Mn

No abstract

No abstract