Annealing-induced grain coarsening and voltage kinks in superconducting NbRe films
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| Main Authors: | , , , , , , , |
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| Format: | Preprint |
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2026
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| author | Kakhaki, Zahra Makhdoumi Pokusinskyi, Anton O. Avitabile, Francesco Kumar, Abhishek Colangelo, Francesco Cirillo, Carla Attanasio, Carmine Dobrovolskiy, Oleksandr V. |
| author_facet | Kakhaki, Zahra Makhdoumi Pokusinskyi, Anton O. Avitabile, Francesco Kumar, Abhishek Colangelo, Francesco Cirillo, Carla Attanasio, Carmine Dobrovolskiy, Oleksandr V. |
| contents | NbRe, a non-centrosymmetric superconductor with a transition temperature $T_\mathrm{c}$ up to 9\,K, attracts interest for its strong antisymmetric spin-orbit coupling and suitability for single-photon detection. While bulk and thin-film polycrystalline NbRe are well studied, how superconductivity and vortex dynamics evolve with increasing grain size in thin films is largely unknown. Here, we investigate as-grown and annealed 20\,nm-thick NbRe films, where annealing increases the average crystallite size from approximately $2$\,nm to $8$\,nm, and study vortex dynamics via current-voltage ($I$-$V$) measurements over a broad temperature and magnetic field range. In contrast to as-grown films, where the low-resistive state breaks down due to flux-flow instability, annealed films exhibit multiple voltage kinks in the $I$-$V$ curves. We attribute these kinks to the nucleation and growth of normal domains, as further suggested by time-dependent Ginzburg-Landau simulations. Overall, the annealed films form superconducting networks with vortex-channeling paths along the grain boundaries, while localized heating and voltage kinks could be harnessed for discrete-resistance switching and sensing. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2604_08735 |
| institution | arXiv |
| publishDate | 2026 |
| record_format | arxiv |
| spellingShingle | Annealing-induced grain coarsening and voltage kinks in superconducting NbRe films Kakhaki, Zahra Makhdoumi Pokusinskyi, Anton O. Avitabile, Francesco Kumar, Abhishek Colangelo, Francesco Cirillo, Carla Attanasio, Carmine Dobrovolskiy, Oleksandr V. Superconductivity NbRe, a non-centrosymmetric superconductor with a transition temperature $T_\mathrm{c}$ up to 9\,K, attracts interest for its strong antisymmetric spin-orbit coupling and suitability for single-photon detection. While bulk and thin-film polycrystalline NbRe are well studied, how superconductivity and vortex dynamics evolve with increasing grain size in thin films is largely unknown. Here, we investigate as-grown and annealed 20\,nm-thick NbRe films, where annealing increases the average crystallite size from approximately $2$\,nm to $8$\,nm, and study vortex dynamics via current-voltage ($I$-$V$) measurements over a broad temperature and magnetic field range. In contrast to as-grown films, where the low-resistive state breaks down due to flux-flow instability, annealed films exhibit multiple voltage kinks in the $I$-$V$ curves. We attribute these kinks to the nucleation and growth of normal domains, as further suggested by time-dependent Ginzburg-Landau simulations. Overall, the annealed films form superconducting networks with vortex-channeling paths along the grain boundaries, while localized heating and voltage kinks could be harnessed for discrete-resistance switching and sensing. |
| title | Annealing-induced grain coarsening and voltage kinks in superconducting NbRe films |
| topic | Superconductivity |
| url | https://arxiv.org/abs/2604.08735 |