Synthesis, structural and transport properties of the hole-doped Superconductor Pr_{1-x}Sr_xFeAsO

TL;DR

This study reports the synthesis and detailed analysis of hole-doped Pr_{1-x}Sr_xFeAsO superconductors, revealing structural changes, superconducting properties, and the dominance of hole carriers, with implications for higher critical fields.

Contribution

It introduces hole doping in PrFeAsO via Sr substitution and systematically investigates its structural, transport, and superconducting properties, highlighting higher upper critical fields compared to electron-doped counterparts.

Findings

Superconductivity achieved at Tc ≈ 16.3 K for x ≈ 0.20-0.25.

Lattice constants increase with Sr doping.

Hole-like carriers dominate as confirmed by Hall effect.

Abstract

Superconductivity was achieved in PrFeAsO by partially substituting Pr^{3+} with Sr^{2+}. The electrical transport properties and structure of this new superconductor Pr_{1-x}Sr_xFeAsO at different doping levels (x = 0.05$\sim$ 0.25) were investigated systematically. It was found that the lattice constants (a-axis and c-axis) increase monotonously with Sr or hole concentration. The superconducting transition temperature at about 16.3 K (95% $\rho_n$) was observed around the doping level of 0.20$\sim$ 0.25. A detailed investigation was carried out in the sample with doping level of x = 0.25. The domination of hole-like charge carriers in this material was confirmed by Hall effect measurements. The magnetoresistance (MR) behavior can be well described by a simple two-band model. The upper critical field of the sample with T_c = 16.3 K (x = 0.25) was estimated to be beyond 45 Tesla. Our results suggest that the hole-doped samples may have higher upper critical fields comparing to the electron-doped ones, due to the higher quasi-particle density of states at the Fermi level.