Normal-state transport properties of PrFeAsO$_{1-x}$F$_y$ superconductor

TL;DR

This study investigates the normal-state electrical transport properties of PrFeAsO$_{1-x}$F$_y$ superconductors, revealing how fluorine doping suppresses magnetic order and enhances electron-phonon interactions, leading to superconductivity at 50 K.

Contribution

It provides detailed analysis of the normal-state resistivity behavior and estimates a large electron-phonon coupling strength in PrFeAsO$_{1-x}$F$_y$ superconductors, highlighting the interplay of magnetic and electronic properties.

Findings

Fluorine doping suppresses spin-density-wave instability.

Normal-state resistivity behavior varies with temperature, indicating strong electron-electron and electron-phonon interactions.

Estimated electron-phonon coupling constant is 1.3.

Abstract

We have synthesized oxygen-deficient fluorine-doped samples of nominal composition PrFeAsO$_{1-x}$F$_y$ to study the normal and superconducting state properties. Resistivity of undoped PrFeAsO exhibits a strong anomaly at around 155 K 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 50 K. The behavior of normal-state resistivity changes from $T^2$-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 $\rho$, we have estimated the electron-phonon coupling strength ($\lambda$) to be quite large (1.3).