Pressure shift of the superconducting T$_{c}$ of (Pr$_{1-x }$Sr$_{x})$FeAsO and Sm(O$_{1-x}$F$_{x})$FeAs

Pressure plays important role in discovery and unraveling physics of novel superconductors.High Tc iron-based layered compounds can be obtained by hole/electron-doping.To determine if a symmetry between electron and hole-doping exists,we investigated pressure-induced shift in T$_{c}$ by carryingout resistivity measurements under hydrostatic pressure on hole-doped Pr$_{1-x }$Sr$_{x}$FeAsO up to 1.8GPa using piston-cylinder clamp cell device.The coexistence of superconductivity {\&} spin-density wave behavior were observed and pressure effects on both being investigated. Four probe resistance measurements show T$_{c}$ increases (+dT$_{c}$/dP) with pressure for under-doped Pr$_{1-x}$Sr$_{x}$FeAsO similar to high-T$_{c}$ cuprates. High pressure can compress crystalline structure of material and force its layers to be closer,which might increase material's T$_{c}$ by improving pressure-induced charge transfer between (Fe$_{2}$As$_{2})$ and (Pr/Sr)O layers. The pressure effect on T$_{c}$ of Pr$_{1-x }$Sr$_{x}$FeAsO is being compared with that of electron doped Sm(O$_{1-x}$F$_{x})$FeAs. The results suggest a symmetry appear to exist between electron and hole-doping Fe-pnictide superconductors.