Limits on the Superconducting Order Parameter in NdFeAsO${}_{1-x}$F${}_y$ from Scanning SQUID Microscopy

C. W. Hicks, T. M. Lippman, M. E. Huber +3

Identifying the symmetry of the superconducting order parameter in the recently-discovered ferro-oxypnictide family of superconductors, RFeAsO${}_{1-x}$F${}_y$, where $R$ is a rare e…