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Gap in KFe2As2 studied by small-angle neutron scattering observations of the magnetic vortex lattice

Type of publication Peer-reviewed
Publikationsform Original article (peer-reviewed)
Author Kawano-Furukawa H, Bowell CJ, White JS, Heslop RW, Cameron AS, Forgan EM, Kihou K, Lee CH, Iyo A, Eisaki H, Saito T, Fukazawa H, Kohori Y, Cubitt R, Dewhurst CD, Gavilano JL, Zolliker M,
Project Interplay of Magnetism and Superconductivity in Unconventional Superconductors
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Original article (peer-reviewed)

Volume (Issue) 84(2)
Page(s) 0274507-1 - 0274507-8
Title of proceedings PHYSICAL REVIEW B
DOI 10.1103/PhysRevB.84.024507


By neutron scattering, we have observed a well-ordered magnetic vortex lattice (VL) in KFe2As2 single crystals. With the field along the c axis, a nearly isotropic hexagonal VL is formed, with no symmetry transitions up to high fields, indicating a small anisotropy of the superconducting state around this axis. This rules out line nodes parallel to the c axis, and thus d-wave or anisotropic s-wave pairing. However, the strong temperature dependence of the signal at T ≪ Tc shows that extremely small gap values exist; these may arise from nodal lines perpendicular to the c axis.