Very High Critical Field and Superior J c ‐Field Performance in NdFeAsO 0.82 F 0.18 with T c of 51 K

A new family of oxypnictide superconductors, LaFeAsO 0.89 F 0.11 , brings new impetus to the field of high‐temperature superconductivity. In this work, we show that the upper critical field values H c2 (48 K) = 13 T and H c2 (0) can exceed 80–230 T in a high‐pressure‐fabricated NdO 0.82 F 0.18 FeAs bulk sample with T c of 51 K. We also demonstrate the superior performance of supercurrent density in fields for this new superconductor.