Field and temperature dependence of the superfluid density in LaFeAsO1-xFx superconductors: a muon spin relaxation study.
We present zero field and transverse field muon spin relaxation experiments on the recently discovered Fe-based superconductor LaFeAsO1-xFx (x=0.075 and x=0.1). The temperature dependence of the deduced superfluid density is consistent with a BCS s-wave or a dirty d-wave gap function, while the field dependence strongly evidences unconventional superconductivity. We obtain the in-plane penetration depth of lambda ab(0)=254(2) nm for x=0.1 and lambda ab(0)=364(8) nm for x=0.075. Further evidence for unconventional superconductivity is provided by the ratio of Tc versus the superfluid density, which is close to the Uemura line of high-Tc cuprates.
Luetkens
H
H
Laboratory for Muon-Spin Spectroscopy, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland. hubertus.luetkens@psi.ch
Klauss
H-H
HH
Khasanov
R
R
Amato
A
A
Klingeler
R
R
Hellmann
I
I
Leps
N
N
Kondrat
A
A
Hess
C
C
Köhler
A
A
Behr
G
G
Werner
J
J
Büchner
B
B