Spin-based computing is emerging as a powerful approach for energy-efficient and high-performance solutions to future data processing hardware. Spintronic devices function by electrically manipulating the collective dynamics of the electron spin, that is inherently non-volatile, nonlinear and fast-operating, and can couple to other degrees of freedom such as photonic and phononic systems. This review explores key advances in integrating magnetic and spintronic elements into computational architectures, ranging from fundamental components like radio-frequency neurons/synapses and spintronic probabilistic-bits to broader frameworks such as reservoir computing and magnetic Ising machines. We discuss hardware-specific and task-dependent metrics to evaluate the computing performance of spin-based components and associate them with physical properties. Finally, we discuss challenges and future opportunities, highlighting the potential of spin-based computing in next-generation technologies.

While the growing utilization of polymers in flexible electronic devices has sparked significant interest in polymer/metal interfaces, spintronic studies of such interfaces remain limited. Here, spin pumping across a polymer/ferromagnet metal interface is systematically studied between hydrogen silsesquioxane (HSQ) oligomer layers (t HSQ = 30, 36, 48 nm) and NiFe (t NiFe = 4, 5, 7, 10 nm) thin films. Using ferromagnetic resonance measurements, strong spin pumping (large linewidth broadening) and a giant spin mixing conductance, reaching 19.8 nm −2 for HSQ = 48 nm are observed, i.e. comparable to that of heavy metals. The results suggest efficient spin transfer across the HSQ/NiFe interface, possibly originating from a combination of spin and orbital pumping, and provide valuable insights for designing self‐powered and flexible spintronic devices utilizing polymers in combination with ferromagnetic materials.

Spin-orbit torque (SOT) presents a promising avenue for energy-efficient spintronics devices, surpassing the limitations of spin transfer torque. While extensively studied in heavy metals, SOT in antiferromagnetic quantum materials remains largely unexplored. Here, we investigate SOT in epitaxial FeSn, a collinear antiferromagnet with a kagome lattice. FeSn exhibits intriguing topological quantum features, including two-dimensional flat bands and Dirac-like surface states, making it an ideal platform for investigating emergent SOT properties. Using spin-torque ferromagnetic resonance, we uncover a six-fold symmetric damping-like SOT in epitaxial-FeSn/Py heterostructures, reflecting the six-fold symmetry of the epitaxial [0001]-oriented FeSn films. Additionally, we observe a substantial unconventional field-like torque, originating from spin currents with out-of-plane spin polarization. This torque exhibits a unique angular dependence-a superposition of six-fold crystalline symmetry and uniaxial symmetry associated with the antiferromagnetic spin Hall effect. Notably, the unconventional field-like torque is enhanced when the RF current flows along the Neel vector in FeSn. Our findings reveal an unconventional spin current anisotropy tunable by crystalline and magnetic symmetry, offering a novel approach for controlling SOT in antiferromagnetic spintronics.

Spin-orbit-torque-driven auto-oscillations in spin Hall nano-oscillators (SHNOs) offer a transformative pathway toward energy-efficient, nanoscale microwave devices for next-generation neuromorphic computing and high-frequency technologies. A key requirement for achieving robust, sustained oscillations is reducing the threshold current (I_th), strongly governed by spin Hall efficiency (θ_SH). However, conventional strategies to enhance θ_SH face trade-offs, including high longitudinal resistivity, interfacial effects, and symmetry-breaking torques that limit performance. Here, we demonstrate a substantial enhancement of the bulk spin Hall effect in PtBi alloys, achieving over a threefold increase in θ_SH, from 0.07 in pure Pt to 0.24 in Pt_94.0Bi_6.0 and 0.19 in Pt_91.3Bi_8.7, as extracted from DC-bias spin-torque ferromagnetic resonance. The enhanced θ_SH originates from bulk-dominated, extrinsic side-jump scattering across all PtBi compositions. Correspondingly, we observe a 42% and 32% reduction in I_th in 100 nm SHNOs based on Co_40Fe_40B_20(3 nm)/Pt_94.0Bi_6.0(4 nm) and Co_40Fe_40B_20(3 nm)/Pt_91.3Bi_8.7(4 nm), respectively. Structural characterization reveals reduced Pt crystallinity, along with emergence of preferred crystallographic orientations upon introducing higher Bi concentrations. Together, these results position PtBi alloys as a compelling alternative to conventional 5d transition metals, enabling enhanced θ_SH and significantly lower I_th, thus opening new avenues for energy-efficient neuromorphic computing and magnetic random access memory.

We propose an asymmetric-nanoconstriction (ANC) design of spin-Hall nano-oscillators (SHNOs) and investigate mutual synchronization of a pair of such devices using micromagnetic simulations. The ANC geometry enables strong dipolar coupling at sub-50 nm separations while preserving independent current bias for each oscillator. We first characterize the auto-oscillation of a single ANC-SHNO, revealing a broad frequency tuning range and a field-controlled crossover between negative and positive nonlinearities. We then demonstrate that two such oscillators can mutually synchronize solely via dipolar stray fields, without electrical or spin-wave coupling. Depending on the bias conditions, the coupled pair exhibits robust in-phase (0°) or out-of-phase (180°) locking. Notably, we find a bias-dependent amplitude correlation: when the oscillators sustain comparable amplitudes, both in-phase and out-of-phase synchronization are accessible, whereas amplitude imbalance drives the system into an out-of-phase state accompanied by suppression of the weaker oscillator. By combining strong conservative coupling with independent frequency and gain control, the ANC-SHNO platform provides a scalable route toward phased oscillator arrays, neuromorphic computing architectures, and experimental exploration of non-Hermitian spintronic dynamics.

We report on a systematic study of spin current-driven collisions of Bloch lines (BLs) in a biaxial antiferromagnet using micromagnetic simulations and a perturbed sine-Gordon theoretical framework. By analyzing the interplay of damping, spin-torque magnitude, and inertial effects of the Néel order parameter, we identify three distinct collision outcomes. At low BL velocities, mutual annihilation occurs, effectively erasing both topological defects. At intermediate velocities, the BLs reflect elastically, reversing their propagation directions without significant energy loss. For high drive currents that yield large BL velocities, the collisions exhibit a “bursting” phenomenon in which additional BLs are generated, leading to complex multi-soliton dynamics. We further show that the tilting of the domain wall ground state, caused by high spin-torque drive, plays a crucial role in governing the velocity and stability of the colliding BLs. These results highlight key dynamical regimes of antiferromagnetic Bloch lines and suggest potential applications in spin-based memory, logic, and neuromorphic computing, where controlled collisions could enable robust, high-speed manipulation of nanoscale topological information carriers.

Spin Hall nano-oscillators (SHNOs) are emerging spintronic oscillators with significant potential for technological applications, including microwave signal generation, and unconventional computing. Despite their promising applications, SHNOs face various challenges, such as high energy consumption and difficulties in growing high-quality thin film heterostructures with clean interfaces. Here, single-layer topological magnetic Weyl semimetals open a possible solution as they possess both intrinsic ferromagnetism and a large spin-orbit coupling due to their topological properties. However, producing such high-quality thin films of magnetic Weyl semimetals that retain their topological properties and Berry curvature remains a challenge. We address these issues with high-quality single-layer epitaxial ferromagnetic Co2MnGa Weyl semimetal thin film-based SHNOs. We observe a giant spin Hall conductivity, σSHC = (6.08 ± 0.02) × 105 (ℏ/2e) Ω-1 m-1, which is an order of magnitude higher than previous reports. Theoretical calculations corroborate the experimental results with a large intrinsic spin Hall conductivity due to presence of a strong Berry curvature. Further, self spin-orbit torque driven magnetization auto-oscillations are demonstrated for the first time, at an ultralow threshold current density of Jth = 6.2 × 1011 A m-2. These findings indicate that magnetic Weyl semimetals have tremendous application potential for developing energy-efficient spintronic devices.

Surface plasmons offer a promising avenue in the pursuit of swift and localized manipulation of magnetism for advanced magnetic storage and information processing technology. However, observing and understanding spatiotemporal interactions between surface plasmons and spins remains challenging, hindering optimal optical control of magnetism. Here, we demonstrate the spatiotemporal observation of patterned ultrafast demagnetization dynamics in permalloy mediated by propagating surface plasmon polaritons with sub-picosecond time- and sub-μm spatial- scales by employing Lorentz ultrafast electron microscopy combined with excitation through transient optical gratings. We discover correlated spatial distributions of demagnetization amplitude and surface plasmon polariton intensity, the latter characterized by photo-induced near-field electron microscopy. Furthermore, by comparing the results with patterned ultrafast demagnetization dynamics without surface plasmon polariton interaction, we show that the demagnetization is not only enhanced but also exhibits a spatiotemporal modulation near a spatial discontinuity (plasmonic hot spot). Our findings shed light on the intricate interplay between surface plasmons and spins, offer insights into the optimized control of optical excitation of magnetic materials and push the boundaries of ultrafast manipulation of magnetism. One promising approach for the manipulation of the magnetic state of materials is to use surface plasmons, however, observing the direct influence of surface plasmons on spins is challenging. Here, Fan et al use Lorentz ultrafast transmission electron microscopy to illuminate the interplay between surface plasmons and spins.

Time-multiplexed Spinwave Ising Machines (SWIMs) have unveiled a route towards miniaturized, low-cost, and low-power solvers of combinatorial optimization problems. While the number of supported spins is limited by the nonlinearity of the spinwave dispersion, other collective excitations, such as surface acoustic waves (SAWs), offer a linear dispersion. Here, we demonstrate an all-to-all, fully FPGA reprogrammable, 50-spin surface acoustic wave-based Ising machine (SAWIM), using a 50-mm-long Lithium Niobate SAW delay line, off-the-shelf microwave components, and a low-cost FPGA. The SAWIM can solve any 50-spin MAX-CUT problem, with arbitrary coupling matrices, in less than 340 $\mu$s consuming only 0.62 mJ, corresponding to close to 3000 solutions per second and a figure of merit of 1610 solutions/W/s. We compare the SAWIM computational results with those of a 100-spin optical Coherent Ising machine and find a higher probability of solution. Moreover, we demonstrate that there is an optimum overall coupling strength between spins at which the probability of the exact solution reaches 100%. The SAWIM illustrates the general merits of solid state wave-based time-multiplexed Ising machines in the microwave domain as versatile platforms for commercially feasible high-performance solvers of combinatorial optimization problems.

Spin–orbit torque can drive auto-oscillations of propagating spin-wave modes in nano-constriction spin Hall nano-oscillators. These modes facilitate both long-range coupling and the possibility of controlling their phase, which is a crucial aspect for device application. Here, we demonstrate variable-phase coupling between two nano-constriction spin Hall nano-oscillators and their mutual synchronization driven by propagating spin waves. Using electrical measurements and phase-resolved micro-focused Brillouin light scattering microscopy, we show that the phase of the mutual synchronization can be tuned by modulating the drive current or the applied field. Our micromagnetic simulations explore the phase tunability using voltage gating. Our results advance the capabilities of mutually synchronized spin Hall nano-oscillators and open the possibilities for applications in spin-wave logic-based devices. Phase tuning of propagating spin waves is a crucial step in the development of devices based on magnons, which are the quanta of spin waves. Now, this has been demonstrated in a device comprising two spin Hall nano-oscillators.

Ultrafast optical control of magnetic textures offers new opportunities for energy-efficient, high-speed spintronic devices. While uniform magnetization reversal via all-optical switching is well established, the formation dynamics of non-uniform domain walls (DWs) under ultrafast excitation remain poorly understood. Here, we use Lorentz ultrafast electron microscopy combined with transient optical grating excitation to directly image the real-time formation of DWs in a ferrimagnetic GdFeCo film. We observe a rapid evolution from disordered spin contrast to ordered DW arrays within 10 ps, including a transient, strongly asymmetric DW state. In a narrow fluence window, short-lived DWs form and spontaneously vanish within picoseconds. Multiscale simulations combining atomistic spin dynamics and micromagnetics reveal a nonlinear nucleation pathway involving a hybrid transition state where localized, unstable spin textures coalesce into metastable DWs. This nonequilibrium mechanism explains the observed asymmetry and spatial ordering, and establishes a framework for controlling spin textures in magnetic materials on femtosecond timescales.

While mutually interacting spin Hall nano-oscillators (SHNOs) hold great promise for wireless communication, neural networks, neuromorphic computing, and Ising machines, the highest number of synchronized SHNOs remains limited to N = 64. Using ultra-narrow 10 and 20-nm nano-constrictions in W-Ta/CoFeB/MgO trilayers, we demonstrate mutually synchronized SHNO networks of up to N = 105,000. The microwave power and quality factor scale as N with new record values of 9 nW and 1.04 × 10^6, respectively. An unexpectedly strong array size dependence of the frequency-current tunability is explained by magnon exchange between nano-constrictions and magnon losses at the array edges, further corroborated by micromagnetic simulations and Brillouin light scattering microscopy. Our results represent a significant step towards viable SHNO network applications in wireless communication and unconventional computing.

Fe[Formula: see text]Sn[Formula: see text] is a topological kagome ferromagnet that possesses numerous Weyl points close to the Fermi energy, which can manifest various unique transport phenomena such as chiral anomaly, anomalous Hall effect, and giant magnetoresistance. However, the magnetodynamic properties of Fe[Formula: see text]Sn[Formula: see text] have not yet been explored. Here, we report, for the first time, the measurements of the intrinsic Gilbert damping constant ([Formula: see text]), and the effective spin mixing conductance (g[Formula: see text]) of Pt/Fe[Formula: see text]Sn[Formula: see text] bilayers for Fe[Formula: see text]Sn[Formula: see text] thicknesses down to 2 nm, for which [Formula: see text] is [Formula: see text], and g[Formula: see text] is [Formula: see text]. The films have a high saturation magnetization, [Formula: see text], and large anomalous Hall coefficient, [Formula: see text]. The large values of g[Formula: see text], together with the topological properties of Fe[Formula: see text]Sn[Formula: see text], make Fe[Formula: see text]Sn[Formula: see text]/Pt bilayers useful heterostructures for the study of topological spintronic devices.

The ever increasing demand for computational power combined with the predicted plateau for the miniaturization of existing silicon-based technologies has made the search for low power alternatives an industrial and scientifically engaging problem. In this work, we explore spintronics-based Ising machines as hardware computation accelerators. We start by presenting the physical platforms on which this emerging field is being developed, the different control schemes and the type of algorithms and problems on which these machines outperform conventional computers. We then benchmark these technologies and provide an outlook for future developments and use-cases that can help them get a running start for integration into the next generation of computing devices.

Nano-constriction spin-Hall nano-oscillators (NC-SHNOs) have garnered considerable interest due to their potential use as efficient and adjustable nano-sized sources of microwave signals, with high-frequency tunability, adaptable design layout, and CMOS compatibility. In order to facilitate system- and circuit-level designs based on the NC-SHNOs, it is essential to have an analytical model capable of predicting the behavior of the NC-SHNO. In this paper, we introduce an analytical model to describe the frequency behavior of a single NC-SHNO in an in-plane magnetic field while considering the Oersted field. The model is divided into two regions based on the direct current value: the "linear-like" and "bullet" modes. Each region is characterized by distinct concepts and equations. The first region, the "linear-like mode," emerges from the nano-constriction edges and progresses toward the center of the active area of the NC-SHNO. In contrast, the second regime, the localized "bullet mode," exhibits negative nonlinearity, where increasing the current will lead to a decrease in frequency. The model's validity is confirmed through experimental data obtained from electrical RF measurements on a single 180nm wide NC-SHNO, and the model demonstrates excellent agreement with experimental data.

Spin Hall nano oscillators (SHNOs) are promising candidates for neuromorphic computing due to their miniaturized dimensions, non-linearity, fast dynamics, and ability to synchronize in long chains and arrays. However, tuning the individual SHNOs in large chains/arrays, which is key to implementing synaptic control, has remained a challenge. Here, we demonstrate circular memristive nano-gates, both precisely aligned and shifted with respect to nano-constriction SHNOs of W/CoFeB/HfO x , with increased quality of the device tunability. Gating at the exact center of the nano-constriction region is found to cause irreversible degradation to the oxide layer, resulting in a permanent frequency shift of the auto-oscillating modes. As a remedy, gates shifted outside of the immediate nano-constriction region can tune the frequency dramatically (>200 MHz) without causing any permanent change to the constriction region. Circular memristive nano-gates can, therefore, be used in SHNO chains/arrays to manipulate the synchronization states precisely over large networks of oscillators.

Optical heterodyne detection is a powerful technique for characterizing a wide range of physical excitations. Here, we use two types of optical heterodyne detection techniques (fundamental and parametric pumping) to microscopically characterize the high-frequency auto-oscillations of single and multiple nano-constriction spin Hall nano-oscillators (SHNOs). To validate the technique and demonstrate its robustness, we study SHNOs made from two different material stacks, NiFe/Pt and W/CoFeB/MgO, and investigate the influence of both the RF injection power and the laser power on the measurements, comparing the optical results to conventional electrical measurements. To demonstrate the key features of direct, non-invasive, submicron, spatial, and phase-resolved characterization of the SHNO magnetodynamics, we map out the auto-oscillation magnitude and phase of two phase-binarized SHNOs used in Ising Machines. This proof-of-concept platform establishes a strong foundation for further extensions, contributing to the ongoing development of crucial characterization techniques for emerging computing technologies based on spintronics devices

Ising machines (IM) have recently been proposed as unconventional hardware-based computation accelerators for solving NP-hard problems. In this work, we present a model for a time-multiplexed IM based on the nonlinear oscillations in a delay line-based resonator and numerically study the effects that the circuit parameters, specifically the compression gain β_r and frequency nonlinearity β_i, have on the IM solutions. We find that the likelihood of reaching the global minimum – the global minimum probability (GMP) – is the highest for a certain range of β_r and β_i located near the edge of the synchronization region of the oscillators. The optimal range remains unchanged for all tested coupling topologies and network connections. We also observe a sharp transition line in the (β_i, β_r) space above which the GMP falls to zero. In all cases, small variations in the natural frequency of the oscillators do not modify the results, allowing us to extend this model to realistic systems.

Fe _3 Sn _2 is a topological kagome ferromagnet that possesses numerous Weyl points close to the Fermi energy, which can manifest various unique transport phenomena such as chiral anomaly, anomalous Hall effect, and giant magnetoresistance. However, the magnetodynamic properties of Fe _3 Sn _2 have not yet been explored. Here, we report, for the first time, the measurements of the intrinsic Gilbert damping constant ( α _int ), and the effective spin mixing conductance (g _eff^↑↓ ) of Pt/Fe _3 Sn _2 bilayers for Fe _3 Sn _2 thicknesses down to 2 nm, for which α _int is (3.8 ± 0.2) × 10^-2 , and g _eff^↑↓ is (11.7 ± 0.6) nm^-2 . The films have a high saturation magnetization, M_S=620 emu cm^-3 , and large anomalous Hall coefficient, R_S=4.6× 10^-10 Ω cm G^-1 . The large values of g _eff^↑↓ , together with the topological properties of Fe _3 Sn _2 , make Fe _3 Sn _2 /Pt bilayers useful heterostructures for the study of topological spintronic devices.