A new layered iron arsenide NaFeAs isostructural with the superconducting lithium analogue, displays evidence for the coexistence of superconductivity and magnetic ordering.
The lithium ions in Lithium iron arsenide phases with compositions close to LiFeAs have been located using powder neutron diffraction. These phases exhibit superconductivity at temperatures at least as high as 16 K demonstrating that superconductivit
y in compounds with [FeAs]- anti-PbO-type anionic layers occurs in compounds with at least three different structure types and occurs for a wide range of As-Fe-As bond angles.
