AI 中文总结
本研究通过金属覆盖层与Ar离子辐照结合的方法，实现了Nb超导薄膜热磁不稳定性的完全抑制，为薄膜超导技术稳定Nb薄膜提供了实用方案。
AI 中文摘要
超导薄膜中的热磁不稳定性可引发磁通雪崩，破坏临界状态并损害超导器件的性能。本研究通过两种互补方法探究垂直磁场下Nb薄膜的稳定性：添加正常金属覆盖层与Ar离子辐照。磁化测量与磁光成像显示，金属层可抑制低外加场下的雪崩起始，而离子辐照通过将雪崩活动的上限阈值移至更低场，减小了不稳定性区域的高场部分。两种方法在同一样品中结合时，这些部分稳定效果可实现热磁不稳定性的完全抑制。具体而言，经注量为5×10^16 ions/cm²的Ar离子辐照后，涂有1μm厚Cu层的Nb薄膜呈现平滑的磁化曲线及无雪崩的磁通穿透，该复合处理恢复了稳定的临界状态行为，为薄膜超导技术中稳定Nb超导薄膜提供了实用途径。
英文摘要
Thermomagnetic instabilities in superconducting films can trigger flux avalanches that disrupt the critical state and impair the performance of superconducting devices. Here we investigate the stabilization of Nb thin films subjected to a perpendicular magnetic field by two complementary approaches: the addition of normal-metal overlayers and Ar ion irradiation. Magnetization measurements and magneto-optical imaging show that the metallic layers suppress the onset of avalanches at low applied fields, whereas ion irradiation reduces the high-field portion of the instability region by shifting the upper threshold for avalanche activity to lower fields. When combined in the same sample, these two partial stabilization effects lead to complete suppression of thermomagnetic instabilities. In particular, a Nb film coated with a 1~\(μ\)m-thick Cu layer after irradiation at a fluence of \(5\times10^{16}\)~ions/cm\(^2\) exhibits smooth magnetization curves and avalanche-free flux penetration. This combined treatment restores stable critical-state behavior and provides a practical route for stabilizing Nb superconducting films in thin-film superconducting technologies.
