npj Spintronics最新文献

{"title":"Structure, control, and dynamics of altermagnetic textures","authors":"O. Gomonay, V. P. Kravchuk, R. Jaeschke-Ubiergo, K. V. Yershov, T. Jungwirth, L. Šmejkal, J. van den Brink, J. Sinova","doi":"10.1038/s44306-024-00042-3","DOIUrl":"10.1038/s44306-024-00042-3","url":null,"abstract":"We present a phenomenological theory of altermagnets, that captures their unique magnetization dynamics and allows modeling magnetic textures in this new magnetic phase. Focusing on the prototypical d-wave altermagnets, e.g., RuO2, we can explain intuitively the characteristic lifted degeneracy of their magnon spectra, by the emergence of an effective sublattice-dependent anisotropic spin stiffness arising naturally from the phenomenological theory. We show that as a consequence the altermagnetic domain walls, in contrast to antiferromagnets, have a finite gradient of the magnetization, with its strength and gradient direction connected to the altermagnetic anisotropy, even for 180° domain walls. This gradient generates a ponderomotive force in the domain wall in the presence of a strongly inhomogeneous external magnetic field, which may be achieved through magnetic force microscopy techniques. The motion of these altermagentic domain walls is also characterized by an anisotropic Walker breakdown, with much higher speed limits of propagation than ferromagnets but lower than antiferromagnets.","PeriodicalId":501713,"journal":{"name":"npj Spintronics","volume":" ","pages":"1-8"},"PeriodicalIF":0.0,"publicationDate":"2024-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s44306-024-00042-3.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141968508","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}

{"title":"Real-time observation of coherent spin wave handedness","authors":"Taewoo Ha, Kyung Ik Sim, Howon Lee, Hyun Jun Shin, Sanghoon Kim, Se Kwon Kim, Jae Hoon Kim, Dong-Soo Han, Young Jai Choi, Byung Cheol Park","doi":"10.1038/s44306-024-00040-5","DOIUrl":"10.1038/s44306-024-00040-5","url":null,"abstract":"Magnonics, a crucial domain in information science and technology, utilizes spin waves in magnets as efficient information carriers. While antiferromagnets have been suggested for versatile magnonic platform because of the coexistence of right- and left-handed spin waves, their energetic degeneracy poses challenges for observation through spectral measurements, limiting their applicability. Recent observations of distinct spin wave handedness within the gigahertz regime have reported but, are yet to be demonstrated in terahertz (THz) frequencies of antiferromagnetic spin waves. Most of all, the coherence of spin waves is a key aspect of quantum information. Here, employing THz time-domain spectroscopy—a direct, precise, and easy probe for monitoring coherent spin wave dynamics—we discern chiral antiferromagnetic spin waves of opposite phase windings in the time domain, noting their handedness reversal across the angular momentum compensation temperature in ferrimagnets. We establish a principle for directly measuring the handedness of coherent antiferromagnetic spin waves in ferrimagnets with net magnetic moment M ≠ 0 but angular momentum L = 0. Our multidimensional access in the time and spectral domain enables the accurate determination of critical temperature and the dynamic observation of coherent chiral spin waves simultaneously in a single experiment, with potential applications in exploring other quantum chiral entities.","PeriodicalId":501713,"journal":{"name":"npj Spintronics","volume":" ","pages":"1-8"},"PeriodicalIF":0.0,"publicationDate":"2024-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s44306-024-00040-5.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141804434","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}

{"title":"Nonlinear orbital and spin Edelstein effect in centrosymmetric metals","authors":"Insu Baek, Seungyun Han, Suik Cheon, Hyun-Woo Lee","doi":"10.1038/s44306-024-00041-4","DOIUrl":"10.1038/s44306-024-00041-4","url":null,"abstract":"Nonlinear spintronics combines nonlinear dynamics with spintronics, opening up new possibilities beyond linear responses. A recent theoretical work [Xiao et al. Phys. Rev. Lett. 130, 166302 (2023)] predicts the nonlinear generation of spin density [nonlinear spin Edelstein effect (NSEE)] in centrosymmetric metals based on symmetry analysis combined with first-principle calculation. This paper focuses on the fundamental role of orbital degrees of freedom for the nonlinear generation in centrosymmetric systems. Using a combination of tight-binding model and density functional theory calculations, we demonstrate that nonlinear orbital density can arise independently of spin–orbit coupling. In contrast, spin density follows through spin–orbit coupling. We further elucidate the microscopic mechanism responsible for this phenomenon, which involves the NSEE induced by electric-field-induced orbital Rashba texture. In addition, we also explore the potential applications of the nonlinear orbital and spin Edelstein effect for magnetic-field-free switching of magnetization.","PeriodicalId":501713,"journal":{"name":"npj Spintronics","volume":" ","pages":"1-7"},"PeriodicalIF":0.0,"publicationDate":"2024-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s44306-024-00041-4.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141639659","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}

{"title":"An energy efficient way for quantitative magnetization switching","authors":"Xin Li, Hanuman Singh, Jie Lin, Shuai Zhang, Bao Yi, Jyotirmoy Chatterjee, Zhuyun Xiao, Sucheta Mondal, Nobumichi Tamura, Rob N. Candler, Long You, Jeffrey Bokor, Jeongmin Hong","doi":"10.1038/s44306-024-00039-y","DOIUrl":"10.1038/s44306-024-00039-y","url":null,"abstract":"Recent advancements in electrically controlled spin devices have been made possible through the use of multiferroic systems comprising ferroelectric (FE) and ferromagnetic (FM) materials. This progress provides a promising avenue for developing energy-efficient devices that allow for electrically controlled magnetization switching. In this study, we fabricated spin orbit torque (SOT) devices using multiferroic composites and examined the angular dependence of SOT effects on localized in-plane strain induced by an out-of-plane electric field applied to the piezoelectric substrate. The induced strain precisely modulates magnetization switching via the SOT effect in multiferroic heterostructures, which also exhibit remarkable capability to modulate strain along different orientations – a feature with great potential for future applications in logic device arrays. To investigate the influence of electric fields on magnetization switching, harmonic Hall measurements, synchrotron-powered x-ray magnetic circular dichroism-photoemission electron microscopy (XMCD-PEEM), x-ray diffraction (XRD), magnetic force microscopy (MFM), and micromagnetic simulation were conducted. The results demonstrate that electric-field-induced strain enables precise control of SOT-induced magnetization switching with significantly reduced energy consumption, making it highly suitable for next-generation spin logic devices.","PeriodicalId":501713,"journal":{"name":"npj Spintronics","volume":" ","pages":"1-8"},"PeriodicalIF":0.0,"publicationDate":"2024-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s44306-024-00039-y.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141639660","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}

{"title":"Observation and enhancement of room temperature bilinear magnetoelectric resistance in sputtered topological semimetal Pt3Sn","authors":"Yihong Fan, Zach Cresswell, Yifei Yang, Wei Jiang, Yang Lv, Thomas J. Peterson, Delin Zhang, Jinming Liu, Tony Low, Jian-Ping Wang","doi":"10.1038/s44306-024-00036-1","DOIUrl":"10.1038/s44306-024-00036-1","url":null,"abstract":"Topological semimetal materials have attracted a great deal of attention due to their intrinsic strong spin-orbit coupling, which leads to large charge-to-spin conversion efficiency and novel spin transport behaviors. In this work, we have observed a bilinear magnetoelectric resistance (BMER) of up to 0.0034 nm2A−1Oe−1 in a single layer of sputtered semimetal Pt3Sn at room temperature. Being different from previous works, the value of BMER in sputtered Pt3Sn does not change out-of-plane due to the polycrystalline nature of the Pt3Sn layer. The observation of BMER provides strong evidence of the existence of spin-momentum locking in the sputtered polycrystalline Pt3Sn. By adding an adjacent CoFeB magnetic layer, the BMER value of this bilayer system is doubled compared to the single Pt3Sn layer. This work broadens the material system in BMER study, which paves the way for the characterization of topological states and applications for spin memory and logic devices.","PeriodicalId":501713,"journal":{"name":"npj Spintronics","volume":" ","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2024-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s44306-024-00036-1.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141639671","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}

{"title":"Wideband coherent microwave conversion via magnon nonlinearity in a hybrid quantum system","authors":"Jiahao Wu, Jiacheng Liu, Zheyu Ren, Man Yin Leung, Wai Kuen Leung, Kin On Ho, Xiangrong Wang, Qiming Shao, Sen Yang","doi":"10.1038/s44306-024-00035-2","DOIUrl":"10.1038/s44306-024-00035-2","url":null,"abstract":"Frequency conversion is a widely realized physical process in nonlinear systems of optics and electronics. As an emerging nonlinear platform, spintronic devices have the potential to achieve stronger frequency conversion. Here, we demonstrated a microwave frequency conversion method in a hybrid quantum system, integrating nitrogen-vacancy centers in diamond with magnetic thin film CoFeB. We achieve a conversion bandwidth ranging from 0.1 to 12 GHz, presenting an up to 25th order frequency conversion and further display the application of this method for frequency detection and qubits coherent control. Distinct from traditional frequency conversion techniques based on nonlinear electric response, our approach employs nonlinear magnetic response in spintronic devices. The nonlinearity, originating from the symmetry breaking such as domain walls in magnetic films, presents that our method can be adapted to hybrid systems of other spintronic devices and spin qubits, expanding the application scope of spintronic devices and providing a promising on-chip platform for coupling quantum systems.","PeriodicalId":501713,"journal":{"name":"npj Spintronics","volume":" ","pages":"1-8"},"PeriodicalIF":0.0,"publicationDate":"2024-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s44306-024-00035-2.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141537066","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}

{"title":"Magnetic anisotropy and GGG substrate stray field in YIG films down to millikelvin temperatures","authors":"Rostyslav O. Serha, Andrey A. Voronov, David Schmoll, Roman Verba, Khrystyna O. Levchenko, Sabri Koraltan, Kristýna Davídková, Barbora Budinská, Qi Wang, Oleksandr V. Dobrovolskiy, Michal Urbánek, Morris Lindner, Timmy Reimann, Carsten Dubs, Carlos Gonzalez-Ballestero, Claas Abert, Dieter Suess, Dmytro A. Bozhko, Sebastian Knauer, Andrii V. Chumak","doi":"10.1038/s44306-024-00030-7","DOIUrl":"10.1038/s44306-024-00030-7","url":null,"abstract":"Quantum magnonics investigates the quantum-mechanical properties of magnons, such as quantum coherence or entanglement for solid-state quantum information technologies at the nanoscale. The most promising material for quantum magnonics is the ferrimagnetic yttrium iron garnet (YIG), which hosts magnons with the longest lifetimes. YIG films of the highest quality are grown on a paramagnetic gadolinium gallium garnet (GGG) substrate. The literature has reported that ferromagnetic resonance (FMR) frequencies of YIG/GGG decrease at temperatures below 50 K despite the increase in YIG magnetization. We investigated a 97 nm-thick YIG film grown on 500 μm-thick GGG substrate through a series of experiments conducted at temperatures as low as 30 mK, and using both analytical and numerical methods. Our findings suggest that the primary factor contributing to the FMR frequency shift is the stray magnetic field created by the partially magnetized GGG substrate. This stray field is antiparallel to the applied external field and is highly inhomogeneous, reaching up to 40 mT in the center of the sample. At temperatures below 500 mK, the GGG field exhibits a saturation that cannot be described by the standard Brillouin function for a paramagnet. Including the calculated GGG field in the analysis of the FMR frequency versus temperature dependence allowed the determination of the cubic and uniaxial anisotropies. We find that the total crystallographic anisotropy increases more than three times with the decrease in temperature down to 2 K. Our findings enable accurate predictions of the YIG/GGG magnetic systems behavior at low and ultralow millikelvin temperatures, crucial for developing quantum magnonic devices.","PeriodicalId":501713,"journal":{"name":"npj Spintronics","volume":" ","pages":"1-7"},"PeriodicalIF":0.0,"publicationDate":"2024-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11219280/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141536332","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}

{"title":"Antiferromagnetic spintronics and beyond","authors":"A. Dal Din, O. J. Amin, P. Wadley, K. W. Edmonds","doi":"10.1038/s44306-024-00029-0","DOIUrl":"10.1038/s44306-024-00029-0","url":null,"abstract":"In this review article, we summarize some recent key results in the development of antiferromagnetic spintronics. Current-induced switching of the Néel vector orientation has now been established in a wide range of antiferromagnetic films and antiferromagnet / heavy metal bilayers, as well as current-driven motion of antiferromagnetic spin textures. The latter are particularly promising due to their small size and topological stability, but reading their magnetic state presents challenges. We also focus on materials whose compensated spin arrangements (either collinear or noncollinear) are coexistent with a spin-split band structure, enabling first-order spintronic phenomena including giant and tunneling magnetoresistance, and the anomalous Hall effect. The resulting combination of efficient electrical readout mechanisms with the advantages of a near-zero net magnetization has potential to be transformative for spintronic applications.","PeriodicalId":501713,"journal":{"name":"npj Spintronics","volume":" ","pages":"1-8"},"PeriodicalIF":0.0,"publicationDate":"2024-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s44306-024-00029-0.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141537068","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}

{"title":"Sub-millimeter propagation of antiferromagnetic magnons via magnon-photon coupling","authors":"Ryo Kainuma, Keita Matsumoto, Toshimitsu Ito, Takuya Satoh","doi":"10.1038/s44306-024-00034-3","DOIUrl":"10.1038/s44306-024-00034-3","url":null,"abstract":"For the realization of magnon-based current-free technologies, referred to as magnonics, all-optical control of magnons is an important technique for both fundamental research and practical applications. Magnon-polariton is a coupled state of magnon and photon in a magnetic medium, expected to exhibit magnon-like controllability and photon-like high-speed propagation. While recent studies have observed magnon-polaritons as modulation of incident terahertz waves, the influence of magnon-photon coupling on magnon propagation properties remains unexplored. This study aimed to observe the spatiotemporal dynamics of coherent magnon-polaritons through time-resolved imaging measurements. BiFeO3 was selected as the sample due to its anticipated strong coupling between magnons and photons. The observed dynamics suggest that antiferromagnetic magnons can propagate over long distances, up to hundreds of micrometers, through strong coupling with photons. These results enhance our understanding of the optical control of magnonic systems, thereby paving the way for terahertz opto-magnonics.","PeriodicalId":501713,"journal":{"name":"npj Spintronics","volume":" ","pages":"1-5"},"PeriodicalIF":0.0,"publicationDate":"2024-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s44306-024-00034-3.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141537077","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}

{"title":"Spintronic devices for biomedical applications","authors":"Shahriar Mostufa, Shuang Liang, Vinit Kumar Chugh, Jian-Ping Wang, Kai Wu","doi":"10.1038/s44306-024-00031-6","DOIUrl":"10.1038/s44306-024-00031-6","url":null,"abstract":"In the past decade, there has been a significant rise in the development of novel spintronic device architectures specifically designed to meet the demands of diverse biomedical applications. These advancements have notably focused on enhancing various bioassay detection techniques, including magnetocardiography and neural signal recording. Through collaboration within the spintronics community, these devices are rapidly transitioning from laboratory prototypes to practical applications, catering to diverse biomedical applications and benefiting both researchers and medical practitioners alike. In this review, we comprehensively explore the biomedical applications of spintronic devices, due to their inherent sensitivity to external magnetic fields, ease of fabrication into large arrays of nano/micro-sized devices within confined spaces, resilience under harsh environmental conditions, and high repeatability. Established spintronics devices that exploit various magnetoresistive effects have already been extensively deployed as magnetic biosensors for disease diagnosis, medical imaging, and bio-magnetic field detection, offering superior sensitivity and robustness. This review aims to provide peers with an up-to-date overview of spintronic devices in biomedical contexts while also commenting on future research trends and challenges. With advancements in nano/microfabrication techniques enhancing device robustness and magnetic field sensitivity, it is foreseeable that these spintronic devices could catalyze revolutionary transformations in healthcare.","PeriodicalId":501713,"journal":{"name":"npj Spintronics","volume":" ","pages":"1-23"},"PeriodicalIF":0.0,"publicationDate":"2024-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s44306-024-00031-6.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141537070","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}