Superconducting properties of SmO1-xFxFeAs wires with Tc = 52 K prepared   by the powder-in-tube method
  We demonstrate that Ta sheathed SmO1-xFxFeAs wires were successfully fabricated by the powder-in-tube (PIT) method for the first time. Structural analysis by mean of x-ray diffraction shows that the main phase of SmO1-xFxFeAs was obtained by this synthesis method. The transition temperature of the SmO0.65F0.35FeAs wires was confirmed to be as high as 52 K. Based on magnetization measurements, it is found that a globe current can flow on macroscopic sample dimensions with Jc of ~3.9x10^3 A/cm^2 at 5 K and self field, while a high Jc about 2x10^5 A/cm^2 is observed within the grains, suggesting that a significant improvement in the globle Jc is possible. It should be noted that the Jc exhibits a very weak field dependence behavior. Furthermore, the upper critical fields (Hc2) determined according to the Werthamer-Helfand-Hohenberg formula are (T= 0 K) = 120 T, indicating a very encouraging application of the new superconductors. 
Zhaoshun Gao, Lei Wang, Yanpeng Qi, Dongliang Wang, Xianping Zhang,   Yanwei Ma, Huan Yang, Haihu Wen