Coupled optical and magnetic excitations can give rise to remarkably strong magneto-optic responses. This is particularly evident in van der Waals magnets, such as the antiferromagnet CrSBr, where excitons and magnons emerge from the same electronic orbitals. While previous work has primarily focused on uncovering the magneto-electric origin of the resulting exciton-magnon interactions, the influence of photonic effects has received comparatively little attention. Here, we use numerical simulations to disentangle exciton-magnon coupling from the exciton-mediated magnon-photon interactions observed in optical experiments. Our simulations show the strong dependence of these interactions on photonic interference and dispersion effects near excitonic resonances. Such effects shape the optical response to coherent magnons and make it intrinsically non-linear in the magnon-induced exciton energy shift. Thermal magnons, which have a particularly pronounced impact on excitons, are found to even produce qualitatively different trends in optical signatures. Depending on weak or strong coupling of excitons and photons, the same exciton-magnon interaction can lead to a red-shift of optical modes, a nearly vanishing response, or their blue-shift. Finally, we demonstrate first steps towards optimizing the multi-parameter problem of efficient magnon-photon transduction using a machine-learning approach.
We demonstrate robust and reversible electric-current control of the anomalous Hall effect (AHE) in a two-dimensional WTe2/Fe3GeTe2 (FGT) stack. Applying a current through Td-WTe2 leads to a giant modulation of the AHE of the adjacent FGT layer, with the relative change of the AHE conductivity exceeding 180
Magnetic skyrmions and related topological spin textures have emerged as a central topic in condensed-matter physics, combining fundamental significance with potential for transformative applications in spintronics, magnonics, and beyond. Over the past decade, advances in material platforms, imaging techniques, theoretical modeling, and device concepts have established skyrmionics as a rapidly expanding field. At the same time, challenges remain in stabilizing, controlling, and integrating such textures into functional architectures, while novel phenomena such as antiskyrmions, higher-order skyrmions, hopfions, and antiferromagnetic textures arise. The 2026 Skyrmionics Roadmap represents a collective effort of many authors, providing a comprehensive perspective on the current state-of-the-art and the outlook for the coming years. In 33 focused sections, each co-authored by two researchers, we chart progress in theory and modeling, material systems, skyrmion dynamics, and skyrmion technologies. By offering a consolidated vision, this Roadmap aims to guide both fundamental research and application-driven efforts, accelerating the transition of skyrmionics from conceptual breakthroughs toward practical technologies.
We experimentally investigate frequency-selective spin wave (SW) transmission in a micrometer-scale, ring-shaped magnonic resonator integrated with a linear yttrium iron garnet stripe. Using super-Nyquist-sampling magneto-optical Kerr effect (SNS-MOKE) microscopyand micro-focused Brillouin light scattering (mu-BLS), we probe SW dynamics in the dipolar regime under in-plane magnetization. Spatially resolved measurements reveal a sharp transmission peak at 3.92 GHz for an external field of 74 mT, demonstrating strong frequency selectivity. This behavior arises from interference and scattering among multiple SW modes in the ring, shaped by anisotropic dispersion, geometric confinement, and local magnetic field inhomogeneities. Caustic-like propagation further limits outcoupling due to fixed group velocity directions. Fourier analysis reveals discrete wavevector components consistent with quantized ring eigenmodes. mu-BLS measurements at 70 mT show a shift of the transmission peak, demonstrating tunability via the external magnetic field. (c) 2025 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution-Non Commercial 4.0International (CC BY-NC) license (https://creativecommons.org/licenses/by-nc/4.0/).
Spin waves, the fundamental excitations in magnetic materials, are promising candidates for realizing low-dissipation information processing in spintronics. The ability to visualize and manipulate coherent spin-wave transport is crucial for the development of spin wave-based devices. We use a recently discovered method utilizing nitrogen vacancy (NV) centers, point defects in the diamond lattice, to measure spin waves in thin film magnetic insulators by detecting their magnetic stray field. We experimentally demonstrate enhanced contrast in the detected wavefront amplitudes by imaging spin waves underneath a reference stripline and phenomenologically model the results. By extracting the spin wave dispersion and comparing NV center based spin wave measurements to spin wave imaging conducted through the well-established time-resolved magneto-optical Kerr effect, we discuss the advantages and limitations of employing NV centers as spin wave sensors.
Efficient spin sources with large spin Hall angle (theta(SH)) and long spin diffusion length (lambda(SD)) are highly desired in the application of spintronic devices. However, due to strong spin-orbit coupling, the two targets can hardly be achieved simultaneously in conventional relativistic spin sources, like heavy metals. Here, it is proven that collinear antiferromagnetic RuO2 films are able to address this key issue and break the inverse relationship of theta(SH) versus lambda(SD). Based on spin torque-ferromagnetic resonance and spin pumping measurements, the authors demonstrate that the theta SH of RuO2(100) films is 0.183, and the lambda(SD) is over 12 nm being an order of magnitude longer than that of Pt, beta-W, and beta-Ta. Meanwhile, sizable lambda SD is also obtained in spin current with out-of-plane spin polarization generated by RuO2(101) films. By conducting a control experiment, the nonrelativistic altermagnetic spin splitting effect (ASSE) is ascertained to be the crucial mechanism accounting for the simultaneous large theta(SH) and long lambda(SD) in RuO2. Besides the fundamental significance, these findings will advance the development of spintronics towards higher efficiency and lower power consumption.
Exploring novel strategies to manipulate the order parameter of magnetic materials by electrical means is of great importance, not only for advancing our understanding of fundamental magnetism, but also for unlocking potential practical applications. A well-established concept to date uses gate voltages to control magnetic properties, such as saturation magnetization, magnetic anisotropies, coercive field, Curie temperature and Gilbert damping, by modulating the charge carrier population within a capacitor structure. Note that the induced carriers are non-spin-polarized, so the control via the electric-field is independent of the direction of the magnetization. Here, we show that the magnetocrystalline anisotropy (MCA) of ultrathin Fe films can be reversibly modified by a spin current generated in Pt by the spin Hall effect. The effect decreases with increasing Fe thickness, indicating that the origin of the modification can be traced back to the interface. Uniquely, the change in MCA due to the spin current depends not only on the polarity of the charge current but also on the direction of magnetization, i.e. the change in MCA has opposite sign when the direction of magnetization is reversed. The control of magnetism by the spin current results from the modified exchange splitting of majority- and minority-spin bands, and differs significantly from the manipulation by gate voltages via a capacitor structure, providing a functionality that was previously unavailable and could be useful in advanced spintronic devices.
The accurate measurement of the Dzyaloshinskii-Moriya interaction (DMI) in ultrathin ferromagnetic/heavy metal heterostructures was recently shown to require extreme experimental care. In this presentation the current state-of-the-art of measuring interfacial DMI is reviewed, and two of the most popular techniques - non-reciprocity of thermally activated magnetostatic spin wave dispersion and asymmetric bubble domain expansion - are discussed for their reliability and applicability. Furthermore, the large discrepancies observed recently between the two techniques are analyzed, and possible origins are discussed. The presentation aims to achieve a deeper comprehension of the reasons behind the discrepancies and to assess the applicability of various techniques to different heterostructures.
As one of the fundamental magnonic devices, magnonic splitter devices have been proposed and spin wave propagation in the devices has been studied numerically and experimentally. In the present work, we fabricated a T-shaped magnonic splitter with three 6 μm-wide arms from a 100 nm-thick yttrium iron garnet film. Using time-resolved magneto-optic Kerr microscopy, we observed spin waves splitting into both, the vertical and the horizontal direction at the junction. Analyzing the results, we found that the spin wave width modes are converted into each other during the splitting process and, consequently, concluded that the width mode conversion efficiency depends on the ratio of wavelength to the vertical branch's width and the anisotropic distribution of the spin wave amplitude at the T-junction.
Reservoir computing is a neuromorphic architecture that may offer viable solutions to the growing energy costs of machine learning. In software-based machine learning, computing performance can be readily reconfigured to suit different computational tasks by tuning hyperparameters. This critical functionality is missing in 'physical' reservoir computing schemes that exploit nonlinear and history-dependent responses of physical systems for data processing. Here we overcome this issue with a 'task-adaptive' approach to physical reservoir computing. By leveraging a thermodynamical phase space to reconfigure key reservoir properties, we optimize computational performance across a diverse task set. We use the spin-wave spectra of the chiral magnet Cu2OSeO3 that hosts skyrmion, conical and helical magnetic phases, providing on-demand access to different computational reservoir responses. The task-adaptive approach is applicable to a wide variety of physical systems, which we show in other chiral magnets via above (and near) room-temperature demonstrations in Co8.5Zn8.5Mn3 (and FeGe).
Physical reservoirs holding intrinsic nonlinearity, high dimensionality, and memory effects have attracted considerable interest regarding solving complex tasks efficiently. Particularly, spintronic and strain-mediated electronic physical reservoirs are appealing due to their high speed, multi-parameter fusion and low power consumption. Here, we experimentally realize a skyrmion-enhanced strain-mediated physical reservoir in a multiferroic heterostructure of Pt/Co/Gd multilayers on (001)-oriented 0.7PbMg 1/3 Nb 2/3 O 3 −0.3PbTiO 3 (PMN-PT). The enhancement is coming from the fusion of magnetic skyrmions and electro resistivity tuned by strain simultaneously. The functionality of the strain-mediated RC system is successfully achieved via a sequential waveform classification task with the recognition rate of 99.3% for the last waveform, and a Mackey-Glass time series prediction task with normalized root mean square error (NRMSE) of 0.2 for a 20-step prediction. Our work lays the foundations for low-power neuromorphic computing systems with magneto-electro-ferroelastic tunability, representing a further step towards developing future strain-mediated spintronic applications.
We investigate the coupled magnetization dynamics in heterostructures of a single crystal of the chiral magnet Cu2OSeO3 (CSO) and a polycrystalline ferromagnet NiFe (Py) thin film using broadband ferromagnetic resonance (FMR) at cryogenic temperatures. We observe the excitation of a hybrid mode (HM) below the helimagnetic transition temperature of CSO. This HM is attributed to the spin dynamics at the CSO/Py interface. We study the HM by measuring its resonance frequencies for in plane rotations of the external magnetic field. We find that the HM exhibits dominantly fourfold anisotropy in contrast to the FMR of CSO and Py.
The Dzyaloshinskii-Moriya interaction (DMI), being one of the origins of chiral magnetism, is currently attracting considerable attention in the research community focusing on applied magnetism and spintronics. For future applications, an accurate measurement of its strength is indispensable. Here we present a review of the state-of-the-art of measuring the coefficient of the Dzyaloshinskii-Moriya interaction, the DMI constant D, focusing on systems where the interaction arises from the interface between two materials (i.e. interfacial DMI). We give an overview of the experimental techniques as well as their theoretical background and models for the quantification of the DMI constant. The measurement techniques are divided into three categories: a) domain wall-based measurements, b) spin wave-based measurements and c) spin-orbit torque-based measurements. We analyze the advantages and disadvantages of each method and compare D values at different interfaces. The review aims to obtain a better understanding of the applicability of the different techniques to various stacks and of the origin of apparent disagreements among literature values.
We report on spin ratchet currents driven by terahertz radiation electric fields in a Co/Pt magnetic metamaterial formed by triangle-shaped holes forming an antidots lattice and subjected to an external magnetic field applied perpendicularly to the metal film plane. We show that for a radiation wavelength substantially larger than the period of the antidots array the radiation causes a polarization-independent spin-polarized ratchet current. The current is generated by the periodic asymmetric radiation intensity distribution caused by the near-field diffraction at the edges of the antidots, which induces spatially inhomogeneous periodic electron gas heating, and a phase-shifted periodic asymmetric electrostatic force. The developed microscopic theory shows that the magnetization of the Co/Pt film results in a spin ratchet current caused by both the anomalous Hall and the anomalous Nernst effects. Additionally, we observed a polarization-dependent trigonal spin photocurrent, which is caused by the scattering of electrons at the antidot boundaries resulting in a spin-polarized current due to the magnetization. Microscopic theory of these effects reveals that the trigonal photocurrent is generated at the boundaries of the triangle antidots, whereas the spin ratchet is generated due to the spatially periodic temperature gradient over the whole film. This difference causes substantially different hysteresis widths of these two currents.
We report resonant elastic x-ray scattering of long-range magnetic order in EuPtSi3, combining different scattering geometries with full linear polarization analysis to unambiguously identify magnetic scattering contributions. At low temperatures, EuPtSi3 stabilizes type A antiferromagnetism featuring various long -wavelength modulations. For magnetic fields applied in the hard magnetic basal plane, well-defined regimes of cycloidal, conical, and fanlike superstructures may be distinguished that encompass a pocket of commensurate type A order without superstructure. For magnetic field applied along the easy axis, the phase diagram comprises the cycloidal and conical superstructures only. Highlighting the power of polarized resonant elastic x-ray scattering, our results reveal a combination of magnetic phases that suggest a highly unusual competition between antiferromagnetic exchange interactions with Dzyaloshinsky-Moriya spin-orbit coupling of similar strength.
We show that magnetic skyrmions can be stabilised at room temperature in continuous [Ir/Co/Pt]5 multilayers on SiO2/Si substrates without the prior application of electric current or magnetic field. While decreasing the Co thickness, a transition of the magnetic domain patterns from worm-like state to separated stripes is observed. The skyrmions are clearly imaged in both states using magnetic force microscopy. The density of skyrmions can be significantly enhanced after applying the “in-plane field procedure”. Our results provide means to manipulate magnetic skyrmion density, further allowing for the optimised engineering of skyrmion-based devices.
Frequency multiplication is an essential part of electronics and optics which led to numerous indispensable ap-plications. In this paper, we utilize a combination of scanning transmission x-ray microscopy and micromagnetic simulations to directly image magnonic frequency multiplication by means of dynamic real-space magnetization measurements. We experimentally demonstrate frequency multiplication up to the seventh order, which enables the generation of nanoscale spin waves at 6 GHz with excitation frequencies of less than 1 GHz. Good agreement between the experiment and micromagnetic simulations allows us to build a micromagnetic model capable of predicting conversion efficiencies and multiplexing capabilities of the system. Furthermore, simulations reveal that more than two rows of antidots do not increase the conversion efficiency substantially. By enabling magnonic multiplexing with low input frequencies while not exceeding the size of a few microns, the device will lead to numerous applications, further advancing the capabilities of magnonic data transmission.
Non-reciprocity in the critical current has been observed in a variety of superconducting systems and has been called the superconducting diode effect. The origin underlying the effect depends on the symmetry breaking mechanisms at play. We investigate superconducting micro-bridges of NbN and also NbN/magnetic insulator (MI) hybrids. We observe a large diode efficiency of ≈30% when an out-of-plane magnetic field as small as 25 mT is applied. In both NbN and NbN/MI hybrid, we find that the diode effect vanishes when the magnetic field is parallel to the sample plane. Our observations are consistent with the critical current being determined by the vortex surface barrier. Unequal barriers on the two edges of the superconductor strip result in the diode effect. Furthermore, the rectification is observed up to 10 K, which makes the device potential for diode based applications over a larger temperature range than before.
Resonant elastic soft X-ray magnetic scattering (XRMS) is a powerful tool to explore long-periodic spin textures in single crystals. However, due to the limited momentum transfer range imposed by long wavelengths of photons in the soft x-ray region, Bragg diffraction is restricted to crystals with the large lattice parameters. Alternatively, small-angle X-ray scattering has been involved in the soft energy X-ray range which, however, brings in difficulties with the sample preparation that involves focused ion beam milling to thin down the crystal to below a few hundred nm thickness. We show how to circumvent these restrictions using XRMS in specular reflection from a sub-nanometer smooth crystal surface. The method allows observing diffraction peaks from the helical and conical spin modulations at the surface of a Cu 2 OSeO 3 single crystal and probing their corresponding chirality as contributions to the dichroic scattered intensity. The results suggest a promising way to carry out XRMS studies on a plethora of noncentrosymmetric systems hitherto unexplored with soft X-rays due to the absence of the commensurate Bragg peaks in the available momentum transfer range.
Current-induced magnetization switching driven by spin–orbit torques on sub-nanosecond timescales could be used to create fast and low-power spintronic devices. The time-resolved detection and analysis of switching trajectories in ferromagnet/antiferromagnet exchange-biased structures are the key to designing spin–orbit torque devices with high speed, but insight remains limited. Here we report the time-resolved detection of spin–orbit torque switching of the magnetization and exchange bias in platinum/cobalt/iridium–manganese heterostructures. Using time-resolved magneto-optical Kerr microscopy, combined with micromagnetic simulations, we show that the ferromagnets, as well as interfacial antiferromagnetic spins and exchange bias, can be partially switched by sub-nanosecond current pulses, which allows the switching probabilities to be flexibly controlled at multiple levels. We also show that the spin–orbit-torque-induced switching of the exchange bias, which intimately depends on the current density, can stabilize multilevelled magnetization switching within sub-nanosecond current pulses. Time-resolved magneto-optical Kerr microscopy, combined with micromagnetic simulations, can be used to detect spin–orbit torque switching of the magnetization and exchange bias in platinum/cobalt/iridium–manganese heterostructures on sub-nanosecond timescales.