Pressure-induced superconductivity in PrOxFeAs

Superconductivity with Tc of 45 K was realized in the tetragonal ZrCuSiAs-type PrOxFeAs (x=0.75) under heat treatment of 1300 oC and pressure of 6 GPa for 2 hours. Although the sample prepared at 900 oC in vaccum possessed the same phase as that treated in pressure, the electrical transport measurement showed the similar behavior with its parent ReOFeAs (Re: rare-earth metal). This pressure-induced superconductivity could give us a hint to understand the origins of the newly-found iron based superconductors.