The London penetration depth was measured in optimally doped Ba 0.6K0.4Fe2As2 crystals, with and without columnar defects produced by 1.4 GeV 208Pb irradiation. The low temperature behavior of unirradiated samples was consistent with a fully gapped superconducting state with a minimum energy gap Δmin/k BTC≈1. Similar gap values were observed for irradiation levels corresponding to mean column-column separations of 32 and 22 nm. At very high irradiation levels (column-column separation of 10 nm) a T2 power law was observed below TC/3, most likely due to elevated scattering. Neither the location nor the sharpness of the superconducting transition was affected by irradiation. The data provide evidence for an s+- pairing state.
|Original language||English (US)|
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|State||Published - May 8 2013|
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics