npj SpintronicsPub Date : 2023-12-13DOI: 10.1038/s44306-023-00002-3
Jeffrey Rable, Jyotirmay Dwivedi, Nitin Samarth
{"title":"Off-resonant detection of domain wall oscillations using deterministically placed nanodiamonds","authors":"Jeffrey Rable, Jyotirmay Dwivedi, Nitin Samarth","doi":"10.1038/s44306-023-00002-3","DOIUrl":"10.1038/s44306-023-00002-3","url":null,"abstract":"Nitrogen-vacancy (NV) centers in diamond offer a sensitive method of measuring the spatially localized dynamics of magnetization and associated spin textures in ferromagnetic materials. We use NV centers in a deterministically positioned nanodiamond to demonstrate off-resonant detection of microwave field-driven GHz-scale oscillations of a single domain wall (DW). The technique exploits the enhanced relaxation of NV center spins due to the broadband stray field noise generated by an oscillating DW pinned at an engineered defect in a lithographically patterned ferromagnetic nanowire. Discrepancies between the observed DW oscillation frequency and predictions from micromagnetic simulations suggest extreme sensitivity of DW dynamics to patterning imperfections such as edge roughness. These experiments and simulations identify potential pathways toward quantum spintronic devices that exploit current-driven DWs as nanoscale microwave generators for qubit control, greatly increasing the driving field at an NV center and thus drastically reducing the π pulse time.","PeriodicalId":501713,"journal":{"name":"npj Spintronics","volume":" ","pages":"1-7"},"PeriodicalIF":0.0,"publicationDate":"2023-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s44306-023-00002-3.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138866182","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
npj SpintronicsPub Date : 2023-11-22DOI: 10.1038/s44306-023-00001-4
Soju Furuta, Wataru Koshibae, Fumitaka Kagawa
{"title":"Symmetry of the emergent inductance tensor exhibited by magnetic textures","authors":"Soju Furuta, Wataru Koshibae, Fumitaka Kagawa","doi":"10.1038/s44306-023-00001-4","DOIUrl":"10.1038/s44306-023-00001-4","url":null,"abstract":"Metals hosting gradually varying spatial magnetic textures are attracting attention as a new class of inductors. Under the application of an alternating current, the spin-transfer-torque effect induces oscillating dynamics of the magnetic texture, which subsequently yields the spin-motive force as a back action, resulting in an inductive voltage response. In general, a second-order tensor representing a material’s response can have an off-diagonal component. However, it is unclear what symmetries the emergent inductance tensor has and also which magnetic textures can exhibit a transverse inductance response. Here, we reveal both analytically and numerically that the emergent inductance tensor should be a symmetric tensor in the so-called adiabatic limit. By considering this symmetric tensor in terms of symmetry operations that a magnetic texture has, we further characterize the magnetic textures in which the transverse inductance response can appear. This finding provides a basis for exploring the transverse response of emergent inductors, which has yet to be discovered.","PeriodicalId":501713,"journal":{"name":"npj Spintronics","volume":" ","pages":"1-7"},"PeriodicalIF":0.0,"publicationDate":"2023-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s44306-023-00001-4.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138866183","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
npj SpintronicsPub Date : 2023-11-22DOI: 10.1038/s44306-023-00004-1
Soju Furuta, Samuel Harrison Moody, Kyohei Kado, Wataru Koshibae, Fumitaka Kagawa
{"title":"Energetic perspective on emergent inductance exhibited by magnetic textures in the pinned regime","authors":"Soju Furuta, Samuel Harrison Moody, Kyohei Kado, Wataru Koshibae, Fumitaka Kagawa","doi":"10.1038/s44306-023-00004-1","DOIUrl":"10.1038/s44306-023-00004-1","url":null,"abstract":"Spatially varying magnetic textures can exhibit electric-current-induced dynamics as a result of the spin-transfer torque effect. When such a magnetic system is electrically driven, an electric field is generated, which is called the emergent electric field. In particular, when magnetic-texture dynamics are induced under the application of an AC electric current, the emergent electric field also appears in an AC manner, notably, with an out-of-phase time profile, thus exhibiting inductor behavior, often called an emergent inductor. Here we show that the emergent inductance exhibited by magnetic textures in the pinned regime can be explained in terms of the current-induced energy stored in the magnetic system. We numerically find that the inductance values defined from the emergent electric field and the current-induced magnetization-distortion energy, respectively, are in quantitative agreement in the so-called adiabatic limit. Our findings indicate that emergent inductors retain the basic concept of conventional inductors; that is, the energy is stored under the application of electric current.","PeriodicalId":501713,"journal":{"name":"npj Spintronics","volume":" ","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2023-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s44306-023-00004-1.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138866184","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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