Superconductivity in co-doped SmFeAsO

Here we report the synthesis and characterizations of SmFe1-xCoxAsO (x = 0.10, 0.15) for the first time. The parent compound SmFeAsO itself is not superconducting but shows an antiferromagnetic order near 150 K, which must be suppressed by doping before superconductivity emerges. With Co doping in the FeAs planes, antiferromagnetic order is destroyed and superconductivity occurs at 15.2 K. Similar to LaFe1-xCoxAsO, the SmFe1-xCoxAsO system appears to tolerate considerable disorder in the FeAs planes. This result is important, suggesting a different mechanism for cuprate superconductors compared to the iron-based arsenide ones.