Performance Boost in Industrial Multifilamentary Nb3Sn Wires due to Radiation Induced Pinning Centers

TL;DR

This study demonstrates that neutron irradiation creates pinning centers in Nb3Sn wires, significantly enhancing their critical current density and performance in high magnetic fields, suggesting new avenues for superconductor optimization.

Contribution

It provides the first evidence that radiation-induced pinning centers can substantially improve the critical current density in multifilamentary Nb3Sn wires.

Findings

Critical current densities reached 4.09×10^9 A/m^2 at 12 T

Jc enhancement of approximately 60% after irradiation

Radiation induced point-pinning centers are responsible

Abstract

We report non-Cu critical current densities of 4.09 * 10^9 A/m^2 at 12 T and 2.27 * 10^9 A/m^2 at 15 T obtained from transport measurements on a Ti-alloyed RRP Nb3Sn wire after irradiation to a fast neutron fluence of 8.9 * 10^21 m^-2. These values are to our knowledge unprecedented in multifilamentary Nb3Sn, and they correspond to a Jc enhancement of approximately 60% relative to the unirradiated state. Our magnetometry data obtained on short wire samples irradiated to fast neutron fluences of up to 2.5 * 10^22 m^-2 indicate the possibility of an even better performance, whereas earlier irradiation studies on bronze-processed Nb3Sn wires with a Sn content further from stoichiometry attested a decline of the critical current density at such high fluences. We show that radiation induced point-pinning centers rather than an increase of the upper critical field are responsible for this Jc enhancement, and argue that these results call for further research on pinning landscape engineering.