Efficient Spin-Orbit Torque Switching in a Magnetic Insulator via Ultrathin Pt and Light Metal Overlayers

Efficient Spin-Orbit Torque Switching in a Magnetic Insulator via Ultrathin Pt and Light Metal Overlayers | 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 Efficient Spin-Orbit Torque Switching in a Magnetic Insulator via Ultrathin Pt and Light Metal Overlayers Stefano Fedel, Can Onur Avci This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7418968/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 10 Feb, 2026 Read the published version in Communications Physics → Version 1 posted You are reading this latest preprint version Abstract Spin-orbit torques (SOTs) are essential for electrically controlling magnetic order in spintronic devices. Platinum (Pt) is ubiquitous for SOT generation due to its strong bulk spin Hall and interfacial Rashba–Edelstein effects. Here, we revisit this established viewpoint by investigating ultrathin Pt films interfaced with a typical magnetic insulator, terbium iron garnet. We find that few-atom-thick, nanogranular Pt exhibits exceptionally efficient SOT-induced switching that cannot be explained by these conventional mechanisms. The efficiency enhancement is attributed to a scattering-mediated extrinsic spin Hall contribution arising from the granular Pt morphology, an effect not previously proposed or observed. Furthermore, adding a titanium (Ti) or manganese (Mn) overlayer to thin Pt enhances the switching efficiency, indicating an active contribution from light metals via orbital current generation. These findings uncover unconventional SOT pathways in ultrathin heterostructures and provide new insights for optimizing spin–orbitronic device performance and enabling energy-efficient magnetic switching. Physical sciences/Materials science/Nanoscale materials/Magnetic properties and materials Physical sciences/Physics/Electronics, photonics and device physics/Electronic and spintronic devices Full Text Additional Declarations There is NO Competing Interest. Supplementary Files EfficientswitchingFedelsupplementary.pdf Supplementary Information for "Efficient Spin-Orbit Torque Switching in a Magnetic Insulator via Ultrathin Pt and Light Metal Overlayers" Cite Share Download PDF Status: Published Journal Publication published 10 Feb, 2026 Read the published version in Communications 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. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. 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-7418968","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":509102215,"identity":"6bf4ca7c-8c5e-40cc-b5fe-c76396f9bdbc","order_by":0,"name":"Stefano Fedel","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAuUlEQVRIiWNgGAWjYDAC5gMMEgwFNjxAJhuRWtgSgFoM0kjXcpiBeC3ybcwHb3wwOC/DP+3wswcMFXWEtRgcY0u2nGFwm0fidpq5AcOZw0Roke8xk+YBajGQTjCTYGw7QIzD+L9J/zE4B9SS/k2C8R8RDmM4xsMmzWBwAKglB2hLAzMRDjvGZmzZY5AM9EtOuUHCMSL8Agyxhzd+VNjZ889O3/bgQw0xDkMBCaRqGAWjYBSMglGAHQAAFY0yDdrWBj8AAAAASUVORK5CYII=","orcid":"https://orcid.org/0000-0002-8116-2428","institution":"Institut de Ciència de Materials de Barcelona","correspondingAuthor":true,"prefix":"","firstName":"Stefano","middleName":"","lastName":"Fedel","suffix":""},{"id":509102216,"identity":"71372273-85c0-42de-a04e-e7c94582d928","order_by":1,"name":"Can Onur Avci","email":"","orcid":"https://orcid.org/0000-0003-1226-2342","institution":"ICMAB-CSIC","correspondingAuthor":false,"prefix":"","firstName":"Can","middleName":"Onur","lastName":"Avci","suffix":""}],"badges":[],"createdAt":"2025-08-20 15:27:50","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-7418968/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7418968/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1038/s42005-026-02539-1","type":"published","date":"2026-02-10T05:00:00+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":105038628,"identity":"34ff0c6f-d483-4c68-9ca2-0a476681e32c","added_by":"auto","created_at":"2026-03-20 07:44:04","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1595096,"visible":true,"origin":"","legend":"Article File","description":"","filename":"EfficientswitchingFedelmanuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7418968/v1_covered_42b90907-46a8-480e-9843-2caefeae7427.pdf"},{"id":91247353,"identity":"ba16e1b5-e67c-45fb-bedd-949b0d7a0163","added_by":"auto","created_at":"2025-09-13 14:25:49","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":2495002,"visible":true,"origin":"","legend":"Supplementary Information for \"Efficient Spin-Orbit Torque Switching in a Magnetic Insulator via Ultrathin Pt and Light Metal Overlayers\"","description":"","filename":"EfficientswitchingFedelsupplementary.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7418968/v1/2e00ed55eaa6fac01808fa98.pdf"}],"financialInterests":"There is \u003cb\u003eNO\u003c/b\u003e Competing Interest.","formattedTitle":"Efficient Spin-Orbit Torque Switching in a Magnetic Insulator via Ultrathin Pt and Light Metal Overlayers","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":true,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":true,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"nature-portfolio","isNatureJournal":true,"hasQc":false,"allowDirectSubmit":false,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"","title":"Nature Portfolio","twitterHandle":"","acdcEnabled":false,"dfaEnabled":false,"editorialSystem":"ejp","reportingPortfolio":"","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"","lastPublishedDoi":"10.21203/rs.3.rs-7418968/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7418968/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"Spin-orbit torques (SOTs) are essential for electrically controlling magnetic order in spintronic devices. Platinum (Pt) is ubiquitous for SOT generation due to its strong bulk spin Hall and interfacial Rashba–Edelstein effects. Here, we revisit this established viewpoint by investigating ultrathin Pt films interfaced with a typical magnetic insulator, terbium iron garnet. We find that few-atom-thick, nanogranular Pt exhibits exceptionally efficient SOT-induced switching that cannot be explained by these conventional mechanisms. The efficiency enhancement is attributed to a scattering-mediated extrinsic spin Hall contribution arising from the granular Pt morphology, an effect not previously proposed or observed. Furthermore, adding a titanium (Ti) or manganese (Mn) overlayer to thin Pt enhances the switching efficiency, indicating an active contribution from light metals via orbital current generation. 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