Superconductivity at 14 K in SmFe0.9Co0.1AsO.

We report superconductivity in the SmFe_0.9Co_0.1AsO system being prepared by most easy and versatile single-step solid-state reaction route. The parent compound SmFeAsO is non-superconducting but shows the spin density wave ( SDW) like antiferromagnetic ordering at around 140 K. To destroy the antiferromagnetic ordering and to induce the superconductivity in the parent system, the Fe²⁺ is partially substituted by Co³⁺. Superconductivity appears in SmFe_0.9Co_0.1AsO system at around 14 K. The Co doping suppresses the SDW anomaly in the parent compound and induces the superconductivity. Magnetization measurements show clearly the onset of superconductivity with T at 14 K. The isothermal magnetization measurements exhibit the lower critical fields ( H_c1) to be around 200 Oe at 2 K. The bulk superconductivity of the studied SmFe_0.9Co_0.1AsO sample is further established by open diamagnetic M( H) loops at 2 and 5 K. Normal-state (above T_c) linear isothermal magnetization M( H) plots excluded the presence of any ordered magnetic impurity in the studied compound. [ABSTRACT FROM AUTHOR]