Superconductivity on the border of itinerant electron ferromagnetism in UGe2

We report on the observation of a superconducting phase in the itinerant el ectron ferromagnet UGe2. The superconductivity observed below 1 K and in a limited pressure range immediately below the critical pressure where ferrom agnetism is abruptly suppressed, would seem to arise from the same electron s that produce band magnetism. This superconductivity is most naturally und erstood in terms of magnetic as opposed to lattice interactions and via a s pin-triplet rather than a spin-singlet pairing normally associated with nea rly anti-ferromagnetic metals. (C) 2001 Elsevier Science B.V. All rights re served.