Normal-state transport properties of PrFeAsO_1−xF_y superconductor

Abstract

We have synthesized oxygen-deficient fluorine-doped samples of nominal composition PrFeAsO1−xFy to study the normal- and superconducting-state properties. Resistivity of undoped PrFeAsO exhibits a strong anomaly at around 155K due to the spin-density-wave instability. Fluorine-doping (x=0.4, y=0.12) suppresses this magnetic instability and drives the system to the superconducting ground state with superconducting onset temperature 50K. The behavior of normal-state resistivity changes from T2-like to T-linear to sublinear in T with increasing temperature indicating that both electron–electron interaction and electron–phonon interaction are strong. From the analysis of T dependence of ρ, we have estimated the electron–phonon coupling strength (λ) to be quite large (1.3).