Iron-Based Layered Superconductor La[O1-xFx]FeAs (x = 0.05−0.12) with Tc = 26 K

We report that a layered iron-based compound LaOFeAs undergoes superconducting transition under doping with F - ions at the O 2- site. The transition temperature ( T c ) exhibits a trapezoid shape dependence on the F - content, with the highest T c of ∼26 K at ∼11 atom %.