title: Superconductivity on the border of itinerant-electron ferromagnetism in UGe2
abstract: The absence of simple examples of superconductivity adjoining itinerant-electron ferromagnetism in the phase diagram has for many years cast doubt on the validity of conventional models of magnetically mediated superconductivity. On closer examination, however, very few systems have been studied in the extreme conditions of purity, proximity to the ferromagnetic state and very low temperatures required to test the theory definitively. Here we report the observation of superconductivity on the border of ferromagnetism in a pure system, UGe2, which is known to be qualitatively similar to the classic d-electron ferromagnets. The superconductivity that we observe below 1 K, in a limited pressure range on the border of ferromagnetism, seems to arise from the same electrons that produce band magnetism. In this case, superconductivity is most naturally understood in terms of magnetic as opposed to lattice interactions, and by a spin-triplet rather than the spin-singlet pairing normally associated with nearly antiferromagnetic metals.
authors.affiliation: Department of Physics, University of Cambridge, UK.
authors.initials: SS
authors.lastname: Saxena
authors.initials: P
authors.lastname: Agarwal
authors.initials: K
authors.lastname: Ahilan
authors.initials: FM
authors.lastname: Grosche
authors.initials: RK
authors.lastname: Haselwimmer
authors.initials: MJ
authors.lastname: Steiner
authors.initials: E
authors.lastname: Pugh
authors.initials: IR
authors.lastname: Walker
authors.initials: SR
authors.lastname: Julian
authors.initials: P
authors.lastname: Monthoux
authors.initials: GG
authors.lastname: Lonzarich
authors.initials: A
authors.lastname: Huxley
authors.initials: I
authors.lastname: Sheikin
authors.initials: D
authors.lastname: Braithwaite
authors.initials: J
authors.lastname: Flouquet