The impact of laser treatment on the microstructure and properties of bronze route Nb3Sn thin films

• Published in: Applied surface science 2025-02, Vol.682, p.161646, Article 161646
• Main Authors: Wang, Changlin, Lu, Ming, Zhang, Jing, Zhang, Bohao, Chu, Qingwei, Tan, Teng, Zhu, Tongtong, Wu, Andong, Zhang, Shengxue, He, Yuan
• Format: Article
• Language: English
• Subjects: Bronze method; Laser annealing; Nb3Sn; Superconductivity; Thermodynamic simulation
• ISSN: 0169-4332
• DOI: 10.1016/j.apsusc.2024.161646

[Display omitted] •The first time using a flat-top laser beam to achieve surface annealing of Nb3Sn film.•Detailed material analysis: structure, processing, properties, and performance.•Reducing defects and decreasing surface roughness of Nb3Sn.•Improving the bonding between Nb3Sn and substrate.•The work reveals the process and mechanism during laser treatment of Nb3Sn. Nb3Sn thin film cavities are new generation of superconducting cavities which have the potential to replace traditional pure niobium cavities owing to their superior theoretical radio frequency (RF) performance. Higher theoretical acceleration gradient and quality factor give Nb3Sn cavities more possibilities in the future. But the RF performance of Nb3Sn cavities is limited by the quench and field emission attributed to their surface defects and there is still none effective way to solve the problem. This study emphasizes a novel Nb3Sn surface treatment method to improve the surface state: laser treatment, achieving a reduction in surface roughness, as well as weakening the Nb3Sn’s grain boundaries and strengthening the bonding between film and substrate. It can also control film thickness without cracks. The issues related to surface improvement mentioned above are tied to the RF loss of Nb3Sn cavities. In this study, a feasible path will be provided for reducing the RF loss and improve the RF performance of Nb3Sn in the future.