Quantifying structural damage from self-irradiation in a plutonium superconductor

TL;DR

This study investigates how self-irradiation damages the crystal structure of the superconductor PuCoGa5, revealing more extensive disorder than current theories predict, which affects its superconducting properties.

Contribution

It provides detailed atomic-scale insights into radiation-induced damage in PuCoGa5, highlighting the discrepancy between observed disorder and existing damage models.

Findings

Superconducting transition temperature decreases rapidly with aging.

Aged material shows much stronger disorder than predicted.

Local lattice distortions significantly impact material properties.

Abstract

The 18.5 K superconductor PuCoGa5 has many unusual properties, including those due to damage induced by self-irradiation. The superconducting transition temperature decreases sharply with time, suggesting a radiation-induced Frenkel defect concentration much larger than predicted by current radiation damage theories. Extended x-ray absorption fine-structure measurements demonstrate that while the local crystal structure in fresh material is well ordered, aged material is disordered much more strongly than expected from simple defects, consistent with strong disorder throughout the damage cascade region. These data highlight the potential impact of local lattice distortions relative to defects on the properties of irradiated materials and underscore the need for more atomic-resolution structural comparisons between radiation damage experiments and theory.