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| Main Authors: | , , , , , , , , , , |
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| Format: | Preprint |
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2024
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| Subjects: | |
| Online Access: | https://arxiv.org/abs/2401.10123 |
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| _version_ | 1866929534697209856 |
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| author | Mottamchetty, Venkatesh Brucas, Rimantas Ravensburg, Anna L. Maciel, Renan Thonig, Danny Henk, Jurgen Gupta, Rahul Roos, Arne Tai, Cheuk Wai Kapaklis, Vassilios Svedlindh, Peter |
| author_facet | Mottamchetty, Venkatesh Brucas, Rimantas Ravensburg, Anna L. Maciel, Renan Thonig, Danny Henk, Jurgen Gupta, Rahul Roos, Arne Tai, Cheuk Wai Kapaklis, Vassilios Svedlindh, Peter |
| contents | We report efficient terahertz (THz) generation in epitaxial $α$-W/Co$_{60}$Fe$_{40}$ spintronic emitters. Two types of emitters have been investigated; epitaxial $α$-W$(110)$/Co$_{60}$Fe$_{40}(110)$ and $α$-W$(001)$/Co$_{60}$Fe$_{40}(001)$ deposited on single crystalline Al$_{2}$O$_{3}$($11\bar{2}0$) and MgO($001$) substrates, respectively. First principle calculations of the electronic band structure at the W$(001)$ surface reveal Dirac-type surface states, similar to that reported previously for the W$(110)$ surface. The generated THz radiation is about $10\%$ larger for $α$-W$(110)$/Co$_{60}$Fe$_{40}(110)$ grown on single crystalline Al$_{2}$O$_{3}$($11\bar{2}0$), which is explained by the fact that the $α$-W$(110)$/Co$_{60}$Fe$_{40}(110)$ interface for this emitter is more transparent to the spin current due to the presence of Ångstr\" om-scale interface intermixing at the W/CoFe interface. Our results also reveal that the generation of THz radiation is larger when pumping with the laser light from the substrate side, which is explained by a larger part of the laser light due to interference effects in the film stack being absorbed in the ferromagnetic Co$_{60}$Fe$_{40}$ layer in this measurement configuration. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2401_10123 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Terahertz emission from $α$-W/CoFe epitaxial spintronic emitters Mottamchetty, Venkatesh Brucas, Rimantas Ravensburg, Anna L. Maciel, Renan Thonig, Danny Henk, Jurgen Gupta, Rahul Roos, Arne Tai, Cheuk Wai Kapaklis, Vassilios Svedlindh, Peter Applied Physics We report efficient terahertz (THz) generation in epitaxial $α$-W/Co$_{60}$Fe$_{40}$ spintronic emitters. Two types of emitters have been investigated; epitaxial $α$-W$(110)$/Co$_{60}$Fe$_{40}(110)$ and $α$-W$(001)$/Co$_{60}$Fe$_{40}(001)$ deposited on single crystalline Al$_{2}$O$_{3}$($11\bar{2}0$) and MgO($001$) substrates, respectively. First principle calculations of the electronic band structure at the W$(001)$ surface reveal Dirac-type surface states, similar to that reported previously for the W$(110)$ surface. The generated THz radiation is about $10\%$ larger for $α$-W$(110)$/Co$_{60}$Fe$_{40}(110)$ grown on single crystalline Al$_{2}$O$_{3}$($11\bar{2}0$), which is explained by the fact that the $α$-W$(110)$/Co$_{60}$Fe$_{40}(110)$ interface for this emitter is more transparent to the spin current due to the presence of Ångstr\" om-scale interface intermixing at the W/CoFe interface. Our results also reveal that the generation of THz radiation is larger when pumping with the laser light from the substrate side, which is explained by a larger part of the laser light due to interference effects in the film stack being absorbed in the ferromagnetic Co$_{60}$Fe$_{40}$ layer in this measurement configuration. |
| title | Terahertz emission from $α$-W/CoFe epitaxial spintronic emitters |
| topic | Applied Physics |
| url | https://arxiv.org/abs/2401.10123 |