Hydrostatic pressure effect on superconductivity and vortex pinning mechanism of Sr(Fe0.88Co0.12)2As2 single crystal

Abstract The external pressure effect on superconducting transition temperature (T c ) was investigated by dc magnetic and electrical resistivity studies for Sr(Fe 0.88 Co 0.12 ) 2 As 2 single crystal down to 2 K. The observed large diamagnetic signal and zero resistance clearly indicate bulk superconductivity with sharp T c of ∼ 16.5 K (0 GPa). Onset of T c is suppressed monotonically down to 5.2 K under pressure up to 2.8 GPa. The evaluation of T c was observed by the application of magnetic fields and critical field was estimated to be rather high of about 10 T. These observed results reveal a large vortex region that replicates high anisotropy of the systems. The observed coherence length ξ GL (0) was estimated to be ∼57 A. We evaluated the thermally activated flux flow activation energy (U 0 ) at 100 K using the Arrhenius equation. Finally, the temperature and pressure dependent critical current density J c (T) and reduced flux pinning force (fp) were analyzed by collective pinning model with different magnetic fields.