Field-induced coupled superconductivity and spin density wave order in the heavy fermion compound CeCoIn5.
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.
Spehling
J
J
Institut für Festkörperphysik, TU Dresden, D-01069 Dresden, Germany.
Heffner
R H
RH
Sonier
J E
JE
Curro
N
N
Wang
C H
CH
Hitti
B
B
Morris
G
G
Bauer
E D
ED
Sarrao
J L
JL
Litterst
F J
FJ
Klauss
H-H
HH