Spin-Torque-Driven Non-uniform Dynamics of an Antivortex Core in Truncated Astroid Shaped Nanomagnets
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| Main Authors: | , , , , , , , , , , , , , , |
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| Format: | Preprint |
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2025
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| _version_ | 1866915229785391104 |
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| author | Aykin, Ahmet Koral Piskin, Hasan Kocaman, Bayram Yanik, Cenk Karakas, Vedat Arpaci, Sevdenur Ozbay, Aisha Gokce Carpentieri, Mario Finocchio, Giovanni Celegato, Federica Tiberto, Paola Lendinez, Sergi Novosad, Valentine Hoffmann, Axel Ozatay, Ozhan |
| author_facet | Aykin, Ahmet Koral Piskin, Hasan Kocaman, Bayram Yanik, Cenk Karakas, Vedat Arpaci, Sevdenur Ozbay, Aisha Gokce Carpentieri, Mario Finocchio, Giovanni Celegato, Federica Tiberto, Paola Lendinez, Sergi Novosad, Valentine Hoffmann, Axel Ozatay, Ozhan |
| contents | Spin textures that are not readily available in the domain structures of continuous magnetic thin films can be stabilized when patterned to micro/nano scales due to the dominant effect of dipolar magnetic interactions. Fabrication of such devices enables a thorough study of their RF dynamics excited by highly concentrated spin-polarized/pure-spin currents. For this purpose, in this study, we have employed a truncated astroid geometry to achieve stable magnetic antivortex core nucleation/annihilation which was detectable using the anisotropic magnetoresistance (AMR) at various temperatures. Furthermore, by depositing a soft magnetic thin film (20 nm thick permalloy) capped with a heavy-metal 2nm Pt layer, we were able to probe the spin orbit torque induced excitations accompanied by self-torque due to half-antivortex cores reminiscent of an isolated-antivortex, yielding GHz frequency oscillations with high quality factors (~50000). The observed RF oscillations can be attributed to a non-uniform domain wall oscillation mode close to the stable-antivortex core nucleation site as seen in micromagnetic simulations. This fundamental study of antivortex core response to spin currents is crucial for the assessment of their potential applications in high frequency spintronic devices such as reservoir computers. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2504_04273 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Spin-Torque-Driven Non-uniform Dynamics of an Antivortex Core in Truncated Astroid Shaped Nanomagnets Aykin, Ahmet Koral Piskin, Hasan Kocaman, Bayram Yanik, Cenk Karakas, Vedat Arpaci, Sevdenur Ozbay, Aisha Gokce Carpentieri, Mario Finocchio, Giovanni Celegato, Federica Tiberto, Paola Lendinez, Sergi Novosad, Valentine Hoffmann, Axel Ozatay, Ozhan Mesoscale and Nanoscale Physics Materials Science Spin textures that are not readily available in the domain structures of continuous magnetic thin films can be stabilized when patterned to micro/nano scales due to the dominant effect of dipolar magnetic interactions. Fabrication of such devices enables a thorough study of their RF dynamics excited by highly concentrated spin-polarized/pure-spin currents. For this purpose, in this study, we have employed a truncated astroid geometry to achieve stable magnetic antivortex core nucleation/annihilation which was detectable using the anisotropic magnetoresistance (AMR) at various temperatures. Furthermore, by depositing a soft magnetic thin film (20 nm thick permalloy) capped with a heavy-metal 2nm Pt layer, we were able to probe the spin orbit torque induced excitations accompanied by self-torque due to half-antivortex cores reminiscent of an isolated-antivortex, yielding GHz frequency oscillations with high quality factors (~50000). The observed RF oscillations can be attributed to a non-uniform domain wall oscillation mode close to the stable-antivortex core nucleation site as seen in micromagnetic simulations. This fundamental study of antivortex core response to spin currents is crucial for the assessment of their potential applications in high frequency spintronic devices such as reservoir computers. |
| title | Spin-Torque-Driven Non-uniform Dynamics of an Antivortex Core in Truncated Astroid Shaped Nanomagnets |
| topic | Mesoscale and Nanoscale Physics Materials Science |
| url | https://arxiv.org/abs/2504.04273 |