Limits on the Superconducting Order Parameter in NdFeAsOF from Scanning SQUID Microscopy
arXiv:0807.0467 · doi:10.1143/JPSJ.78.013708
Abstract
Identifying the symmetry of the superconducting order parameter in the recently-discovered ferro-oxypnictide family of superconductors, RFeAsOF, where is a rare earth, is a high priority. Many of the proposed order parameters have internal phase shifts, like the d-wave order found in the cuprates, which would result in direction-dependent phase shifts in tunnelling. In dense polycrystalline samples, these phase shifts in turn would result in spontaneous orbital currents and magnetization in the superconducting state. We perform scanning SQUID microscopy on a dense polycrystalline sample of \NdFeAsOF with K and find no such spontaneous currents, ruling out many of the proposed order parameters.
10 pages, 5 figures; to appear in JPSJ
References in corpus (6)
- Magnetic Order versus superconductivity in the Iron-based layered La(O1-xFx)FeAs systems
- Unconventional pairing originating from disconnected Fermi surfaces in superconducting LaFeAsOF}
- Superconductivity at 41 K and its competition with spin-density-wave instability in layered CeOFFeAs
- Magnetism, superconductivity, and pairing symmetry in Fe-based superconductors
- Strong Correlations and Magnetic Frustration in the High Tc Iron Pnictides
- Evidence for two distinct scales of current flow in polycrystalline Sm and Nd iron oxypnictides