Resistivity saturation in PrFeAsO1−xFy superconductor: evidence of strong electron–phonon coupling
We have measured the resistivity of PrFeAsO1−xFy samples over a wide range of temperature in order to elucidate the role of electron–phonon interaction on normal- and superconducting-state properties. The linear T dependence of ρ above 170 K followed by a saturation-like behavior at higher temperature is a clear signature of strong electron–phonon coupling. From the analysis of the T dependence of ρ, we have estimated several normal-state parameters that are useful for understanding the origin of superconductivity in this system. Our results suggest that Fe-based oxypnictides are phonon-mediated BCS superconductors like Chevrel phases and A15 compounds.