Speaker
Description
At Helmholtz-Zentrum Berlin (HZB), the Bronze Route is being developed as an alternative synthesis route for Nb₃Sn thin films on both Nb and Cu substrates. Recent work has focused on optimizing precursor composition, electroplating parameters, substrate preparation, reaction conditions, and post-processing to improve phase purity, microstructure, and superconducting performance. Particular emphasis is placed on understanding the influence of substrate quality, Nb diffusion barriers on Cu substrates, Sn concentration, and chemical surface treatments on Nb₃Sn formation.
The coatings are characterized by SEM, EDX and XRD to establish process–structure relationships, while their superconducting performance is evaluated by RF surface resistance measurements using HZB’s Quadrupole Resonator. In addition, the degree of flux-trapping, including thermo-current generated flux, is investigated using the recently commissioned CRAFT facility. The combination of these tools allows us to correlate microstructural features with RF losses, including those caused by trapped flux. The presented results demonstrate the progress of the Bronze Route towards a reproducible coating technology for Nb₃Sn thin films and provide new insights into the relationship between processing, microstructure, and superconducting performance.