Neutron-irradiation effects in LaO0.9F0.1FeAs superconductor

TL;DR

This study investigates how neutron irradiation-induced atomic disorder affects the superconducting and normal state properties of LaO0.9F0.1FeAs, revealing that disorder suppresses superconductivity in a manner consistent with unconventional pairing mechanisms.

Contribution

It demonstrates that neutron-induced atomic disorder suppresses superconductivity and that this suppression aligns with Abrikosov-Gorkov theory, indicating unconventional pairing in Fe-based superconductors.

Findings

Superconductivity is suppressed by neutron irradiation and recovers after annealing.

Suppression of Tc is influenced by electronic relaxation time, not just doping level.

The behavior aligns with the Abrikosov-Gorkov equation, suggesting unconventional pairing.

Abstract

The effect of atomic disorder induced by neutrons irradiation on superconducting and normal state properties of polycrystalline LaFeAsO_0.9F_0.1 was investigated. The irradiation of the sample by a moderate neutron fluence F = 1.6*1019 cm^-2 at Tirr = 50 +- 10 C leads to the suppression of superconductivity which recovers almost completely after annealing at temperatures Tann < 750 C. It is shown that the reduction of superconducting transition temperature Tc under atomic disordering is not determined solely by the value of Hall concentration nH, i.e. doping level, but is governed by the reduction of electronic relaxation time. This behavior can be described qualitatively by universal Abrikosov-Gorkov equation which presents evidence on the anomalous type of electrons pairing in Fe-based superconductors.