title: Field-induced coupled superconductivity and spin density wave order in the heavy fermion compound CeCoIn5.
abstract: The high-field superconducting state in CeCoIn(5) has been studied by transverse field muon spin rotation measurements with an applied field parallel to the crystallographic c axis close to the upper critical field mu(0)H(c2) = 4.97 T. At magnetic fields mu(0)H > or = 4.8 T the muon Knight shift is enhanced and the superconducting transition changes from second order towards first order as predicted for Pauli-limited superconductors. The field and temperature dependence of the transverse muon spin relaxation rate sigma reveal paramagnetic spin fluctuations in the field regime from 2 T < or = mu(0)H < 4.8 T. In the normal state close to H(c2) correlated spin fluctuations as described by the self-consistent renormalization theory are observed. The results support the formation of a mode-coupled superconducting and antiferromagnetically ordered phase in CeCoIn(5) for H directed parallel to the c axis.
authors.affiliation: Institut für Festkörperphysik, TU Dresden, D-01069 Dresden, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Spehling
authors.forename: R H
authors.initials: RH
authors.lastname: Heffner
authors.forename: J E
authors.initials: JE
authors.lastname: Sonier
authors.forename: N
authors.initials: N
authors.lastname: Curro
authors.forename: C H
authors.initials: CH
authors.lastname: Wang
authors.forename: B
authors.initials: B
authors.lastname: Hitti
authors.forename: G
authors.initials: G
authors.lastname: Morris
authors.forename: E D
authors.initials: ED
authors.lastname: Bauer
authors.forename: J L
authors.initials: JL
authors.lastname: Sarrao
authors.forename: F J
authors.initials: FJ
authors.lastname: Litterst
authors.forename: H-H
authors.initials: HH
authors.lastname: Klauss