Superconducting properties of SmFeAsO1−x prepared under high-pressure condition

Synthetic conditions such as stoichiometries, temperature and pressure are optimized to achieve a high quality oxygen deficient SmFeAsO0.6 superconductor. Both electric and magnetic measurements show a sharp superconducting transition at about 55 K. Several important physical parameters are deduced. The apparent superconducting gap observed in heat capacity with 2Δo/kBTc of 4.57 larger than that of previous fluorine replaced samples indicate that this superconductivity will not strongly conflict with the phonon-mediated BCS mechanism. The mean free length ℓ=18.8 nm and the coherent length ξ=2.3–3.3 nm show that the superconductivity is in the clean limit.