npj Spintronics最新文献

{"title":"Author Correction: Antiferromagnetic tunnel junctions for spintronics","authors":"Ding-Fu Shao, Evgeny Y. Tsymbal","doi":"10.1038/s44306-024-00037-0","DOIUrl":"10.1038/s44306-024-00037-0","url":null,"abstract":"","PeriodicalId":501713,"journal":{"name":"npj Spintronics","volume":" ","pages":"1-1"},"PeriodicalIF":0.0,"publicationDate":"2024-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s44306-024-00037-0.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141435708","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":"Celebrating 1 year of npj Spintronics","authors":"Elke Arenholz","doi":"10.1038/s44306-024-00032-5","DOIUrl":"10.1038/s44306-024-00032-5","url":null,"abstract":"","PeriodicalId":501713,"journal":{"name":"npj Spintronics","volume":" ","pages":"1-1"},"PeriodicalIF":0.0,"publicationDate":"2024-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s44306-024-00032-5.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141304305","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":"Multiferroic kinks and spin-flop transition in Ni2InSbO6 from first principles","authors":"Ryota Ono, Igor Solovyev, Sergey Artyukhin","doi":"10.1038/s44306-024-00020-9","DOIUrl":"10.1038/s44306-024-00020-9","url":null,"abstract":"Magnetoelectric multiferroics are key materials for next-generation spintronic devices due to their entangled magnetic and ferroelectric properties. Spiral multiferroics possess ferroelectric polarization and are particularly promising for electric control of magnetism and magnetic control of ferroelectricity. In this work, we uncover long-period incommensurate states characterized by unique multiferroic kinks in corundum nickelate Ni2InSbO6, a member of a promising family of polar magnets. Utilizing a 2-orbital S = 1 model, we derive formulas for Heisenberg and anisotropic magnetic exchanges and magnetically-induced polarization, enabling their calculations from first principles. We use these parameters in Monte Carlo and Landau theory-based calculations to reproduce experimentally observed magnetic structures and polarization dependence on the magnetic field. We predict magnetic phase transitions between flat spiral, conical spiral, canted antiferromagnetic and ferromagnetic states under increasing magnetic fields. Kinks in the spiral phases repel each other through a Yukawa-like potential arising from exchange of massive magnons. We also find that suitably directed electric fields can be used to stabilize the ferromagnetic and spiral states. The findings open a new pathway to predictive first-principles modelling of multiferroics and will inspire experiments and technological applications based on multiferroic kinks.","PeriodicalId":501713,"journal":{"name":"npj Spintronics","volume":" ","pages":"1-10"},"PeriodicalIF":0.0,"publicationDate":"2024-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s44306-024-00020-9.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141246220","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":"High-temperature Néel skyrmions in Fe3GaTe2 stabilized by Fe intercalation into the van der Waals gap","authors":"Rana Saha, Holger L. Meyerheim, Börge Göbel, Ingrid Mertig, Stuart S. P. Parkin","doi":"10.1038/s44306-024-00024-5","DOIUrl":"10.1038/s44306-024-00024-5","url":null,"abstract":"Two-dimensional (2D) van der Waals (vdW) magnets that exhibit ferromagnetism at ambient temperature show great promise for spintronic applications. However, until now, only a few pristine or doped 2D magnets have demonstrated the ability to host non-collinear spin textures, thereby limiting their potential applications. Here we directly observe Néel-type skyrmions in the metallic vdW magnetic compound Fe3GaTe2 (FGaT) up to temperatures well above room temperature (≈340 K) in the absence of any external magnetic field. We show that the presence of defects in the structure of FGaT make its structure acentric and therefore compatible with hosting skyrmions that would otherwise not be possible. Indeed, in this regard it is very similar to the closely related compound Fe3GeTe2 (FGT), whose structure with the same space group P3m1 is also realized by defects. Interestingly, however, FGaT accommodates a significantly higher concentration of Fe within the vdW gaps, likely accounting for its enhanced Curie temperature (TC). In addition to the Néel skyrmions observed in the temperature range of 250–340 K, we also detect type-I and -II Bloch-type skyrmionic bubbles in the temperature range of 100–200 K due to an enhanced magnitude of dipole-dipole interactions relative to the Dzyaloshinskii-Moriya exchange interaction. Self-intercalation is thus a highly interesting property of vdW magnets that considerably modifies their fundamental properties.","PeriodicalId":501713,"journal":{"name":"npj Spintronics","volume":" ","pages":"1-7"},"PeriodicalIF":0.0,"publicationDate":"2024-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s44306-024-00024-5.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141246232","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":"Perspective: There is plenty of room for magnetic straintronics in the analog domain","authors":"Supriyo Bandyopadhyay","doi":"10.1038/s44306-024-00018-3","DOIUrl":"10.1038/s44306-024-00018-3","url":null,"abstract":"Magnetic straintronics made its debut more than a decade ago as an extremely energy-efficient paradigm for implementing a digital switch for digital information processing. The switch consists of a slightly elliptical nano-sized magnetostrictive disk in elastic contact with a poled ultrathin piezoelectric layer (forming a two-phase multiferroic system). Because of the elliptical shape, the nanomagnet’s magnetization has two stable (mutually antiparallel) orientations along the major axis, which can encode the binary bits 0 and 1. A voltage pulse of sub-ns duration and amplitude few to few tens of mV applied across the piezoelectric generates enough strain in the nanomagnet to switch its magnetization from one stable state to the other by virtue of the inverse magnetostriction (or Villari) effect, with an energy expenditure that is roughly an order of magnitude smaller than what it takes to switch a modern-day electronic transistor. That possibility, along with the fact that such a switch is non-volatile unlike the conventional transistor, generated significant excitement. However, it was later tempered by the realization that straintronic switching is also extremely error-prone, which may preclude many digital applications, particularly in Boolean logic. In this perspective, we offer the view that there is plenty of room for magnetic straintronics in the analog domain, which is much more forgiving of switching errors, and where the excellent energy-efficiency and non-volatility are a boon. Analog straintronics can have intriguing applications in many areas, such as a new genre of aggressively miniaturized electromagnetic antennas that defy the Harrington limits on the gain and radiation efficiency of conventional antennas, analog arithmetic multipliers (and ultimately vector matrix multipliers) for non-volatile deep learning networks with very small footprint and excellent energy-efficiency, and relatively high-power microwave oscillators with output frequency in the X-band. When combined with spintronics, analog straintronics can also implement a new type of spin field effect transistor employing quantum materials such as topological insulators, and they have unusual transfer characteristics which can be exploited for analog tasks such as frequency multiplication using just a single transistor. All this hints at a world of new possibilities in the analog domain that deserves serious attention.","PeriodicalId":501713,"journal":{"name":"npj Spintronics","volume":" ","pages":"1-15"},"PeriodicalIF":0.0,"publicationDate":"2024-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s44306-024-00018-3.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141246208","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":"Inducing a tunable skyrmion-antiskyrmion system through ion beam modification of FeGe films","authors":"M. B. Venuti, Xiyue S. Zhang, Eric J. Lang, Sadhvikas J. Addamane, Hanjong Paik, Portia Allen, Peter Sharma, David Muller, Khalid Hattar, Tzu-Ming Lu, Serena Eley","doi":"10.1038/s44306-024-00013-8","DOIUrl":"10.1038/s44306-024-00013-8","url":null,"abstract":"Skyrmions and antiskyrmions are nanoscale swirling textures of magnetic moments formed by chiral interactions between atomic spins in magnetic noncentrosymmetric materials and multilayer films with broken inversion symmetry. These quasiparticles are of interest for use as information carriers in next-generation, low-energy spintronic applications. To develop skyrmion-based memory and logic, we must understand skyrmion-defect interactions with two main goals—determining how skyrmions navigate intrinsic material defects and determining how to engineer disorder for optimal device operation. Here, we introduce a tunable means of creating a skyrmion-antiskyrmion system by engineering the disorder landscape in FeGe using ion irradiation. Specifically, we irradiate epitaxial B20-phase FeGe films with 2.8 MeV Au4+ ions at varying fluences, inducing amorphous regions within the crystalline matrix. Using low-temperature electrical transport and magnetization measurements, we observe a strong topological Hall effect with a double-peak feature that serves as a signature of skyrmions and antiskyrmions. These results are a step towards the development of information storage devices that use skyrmions and antiskyrmions as storage bits, and our system may serve as a testbed for theoretically predicted phenomena in skyrmion-antiskyrmion crystals.","PeriodicalId":501713,"journal":{"name":"npj Spintronics","volume":" ","pages":"1-10"},"PeriodicalIF":0.0,"publicationDate":"2024-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s44306-024-00013-8.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141246215","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":"Epsilon-near-zero regime for ultrafast opto-spintronics","authors":"C. S. Davies, A. Kirilyuk","doi":"10.1038/s44306-024-00025-4","DOIUrl":"10.1038/s44306-024-00025-4","url":null,"abstract":"Over the last two decades, breakthrough works in the field of non-linear phononics have revealed that high-frequency lattice vibrations, when driven to high amplitude by mid- to far-infrared optical pulses, can bolster the light-matter interaction and thereby lend control over a variety of spontaneous orderings. This approach fundamentally relies on the resonant excitation of infrared-active transverse optical phonon modes, which are characterized by a maximum in the imaginary part of the medium’s permittivity. Here, in this Perspective article, we discuss an alternative strategy where the light pulses are instead tailored to match the frequency at which the real part of the medium’s permittivity goes to zero. This so-called epsilon-near-zero regime, popularly studied in the context of metamaterials, naturally emerges to some extent in all dielectric crystals in the infrared spectral range. We find that the light-matter interaction in the phononic epsilon-near-zero regime becomes strongly enhanced, yielding even the possibility of permanently switching both spin and polarization order parameters. We provide our perspective on how this hitherto-neglected yet fertile research area can be explored in future, with the aim to outline and highlight the exciting challenges and opportunities ahead.","PeriodicalId":501713,"journal":{"name":"npj Spintronics","volume":" ","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2024-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s44306-024-00025-4.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141246209","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":"Non-Hermitian Casimir effect of magnons","authors":"Kouki Nakata, Kei Suzuki","doi":"10.1038/s44306-024-00017-4","DOIUrl":"10.1038/s44306-024-00017-4","url":null,"abstract":"There has been a growing interest in non-Hermitian quantum mechanics. The key concepts of quantum mechanics are quantum fluctuations. Quantum fluctuations of quantum fields confined in a finite-size system induce the zero-point energy shift. This quantum phenomenon, the Casimir effect, is one of the most striking phenomena of quantum mechanics in the sense that there are no classical analogs and has been attracting much attention beyond the hierarchy of energy scales, ranging from elementary particle physics to condensed matter physics, together with photonics. However, the non-Hermitian extension of the Casimir effect and the application to spintronics have not yet been investigated enough, although exploring energy sources and developing energy-efficient nanodevices are its central issues. Here we fill this gap. By developing a magnonic analog of the Casimir effect into non-Hermitian systems, we show that this non-Hermitian Casimir effect of magnons is enhanced as the Gilbert damping constant (i.e., the energy dissipation rate) increases. When the damping constant exceeds a critical value, the non-Hermitian Casimir effect of magnons exhibits an oscillating behavior, including a beating one, as a function of the film thickness and is characterized by the exceptional point. Our result suggests that energy dissipation serves as a key ingredient of Casimir engineering.","PeriodicalId":501713,"journal":{"name":"npj Spintronics","volume":" ","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2024-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s44306-024-00017-4.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141246228","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":"Multiferroics: different routes to magnetoelectric coupling","authors":"Maxim Mostovoy","doi":"10.1038/s44306-024-00021-8","DOIUrl":"10.1038/s44306-024-00021-8","url":null,"abstract":"The simultaneous presence of ferroelectricity and magnetism in multiferroics breaks both spatial inversion and time reversal symmetries at the macroscopic scale, which opens the door to many interesting phenomena and resembles the violation of these symmetries in particle physics. The symmetry breaking in multiferroics occurs spontaneously at phase transitions rather than at the level of fundamental interactions, and thus can be controlled. Moreover, each crystal is a universe in itself with a unique set of symmetries, coupling constants and ordered patterns, which presents plenty of opportunities to find and design materials with strong magnetoelectric coupling.","PeriodicalId":501713,"journal":{"name":"npj Spintronics","volume":" ","pages":"1-7"},"PeriodicalIF":0.0,"publicationDate":"2024-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s44306-024-00021-8.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141246225","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":"A quantum sensing metrology for magnetic memories","authors":"Vicent J. Borràs, Robert Carpenter, Liza Žaper, Siddharth Rao, Sebastien Couet, Mathieu Munsch, Patrick Maletinsky, Peter Rickhaus","doi":"10.1038/s44306-024-00016-5","DOIUrl":"10.1038/s44306-024-00016-5","url":null,"abstract":"Magnetic random access memory (MRAM) is a leading emergent memory technology that is poised to replace current non-volatile memory technologies such as eFlash. However, controlling and improving distributions of device properties becomes a key enabler of new applications at this stage of technology development. Here, we introduce a non-contact metrology technique deploying scanning NV magnetometry (SNVM) to investigate MRAM performance at the individual bit level. We demonstrate magnetic reversal characterization in individual, <60 nm-sized bits, to extract key magnetic properties, thermal stability, and switching statistics, and thereby gauge bit-to-bit uniformity. We showcase the performance of our method by benchmarking two distinct bit etching processes immediately after pattern formation. In contrast to ensemble averaging methods such as perpendicular magneto-optical Kerr effect, we show that it is possible to identify out of distribution (tail-bits) bits that seem associated to the edges of the array, enabling failure analysis of tail bits. Our findings highlight the potential of nanoscale quantum sensing of MRAM devices for early-stage screening in the processing line, paving the way for future incorporation of this nanoscale characterization tool in the semiconductor industry.","PeriodicalId":501713,"journal":{"name":"npj Spintronics","volume":" ","pages":"1-7"},"PeriodicalIF":0.0,"publicationDate":"2024-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s44306-024-00016-5.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141246198","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}