Superconductivity at 55 K in iron-based F-doped layered quaternary compound Sm[O1-xFx]FeAs

Here we report the superconductivity in the iron-based oxyarsenide Sm[O1-xFx]FeAs, with the onset resistivity transition temperature at 55.0 K and Meissner transition at 54.6 K. This compound has the same crystal structure as LaOFeAs with shrunk crystal lattices, and becomes the superconductor with the highest critical temperature among all materials besides copper oxides.