Iron-Based Layered Superconductor LaO1-xFxFeAs (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 O2- site. The transition temperature (Tc) exhibits a trapezoid shape dependence on the F- content, with the highest Tc of ∼26 K at ∼11 atom %.