Laser-induced nucleation of magnetic hopfions

Laser-induced nucleation of magnetic hopfions | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Article Laser-induced nucleation of magnetic hopfions Fengshan Zheng, Xiaowen Chen, Donghai Yang, Zefang Li, Jiangteng Guo, and 15 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7435743/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 21 Apr, 2026 Read the published version in Nature Physics → Version 1 posted You are reading this latest preprint version Abstract Hopfions are three-dimensional topological solitons formed by closed loops of vortex strings, typically taking the shape of rings. In magnetic crystals, hopfions have so far been observed only in unusual configurations, where hopfion rings are linked to skyrmion strings. Although theory predicts the existence of stable, isolated hopfions, their experimental realization has remained elusive. Here, we report the laser-induced nucleation and direct observation of isolated magnetic hopfions in cubic chiral magnets using transmission electron microscopy. The nucleation conditions are mapped out as a function of laser fluence and external magnetic field. Good agreement between experimental data and micromagnetic simulations unambiguously confirms the emergence of isolated hopfions and reveals their detailed structure. We derive the topological invariant for hopfions under realistic rather than idealized boundary conditions, and calculate its integer values for the observed objects. We also demonstrate that hopfions can coexist and interact with other topological spin textures over a broad field range. These findings establish a contact-free approach for nucleating and controlling complex three-dimensional magnetic hopfions, opening new directions for both fundamental research and potential applications. Physical sciences/Physics/Condensed-matter physics/Magnetic properties and materials Physical sciences/Physics/Condensed-matter physics/Spintronics Full Text Additional Declarations There is NO Competing Interest. Supplementary Files extendeddatavideo1.mp4 Homotopy showing the unwinding of a hopfion ring by a heliknoton extendeddatavideo2.mp4 In situ nucleation of magnetic hopfions and other textures with ultrafast laser pulses Cite Share Download PDF Status: Published Journal Publication published 21 Apr, 2026 Read the published version in Nature Physics → Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-7435743","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":528712347,"identity":"3302eba7-e8fa-499e-81cf-5a5caafa91d8","order_by":0,"name":"Fengshan 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