This article contains my personal account on how I got interested in spin transport phenomena, which ultimately resulted in investigating multiple facets of spin–orbit torques, as well as magnetization dynamics. Originally this research focused on questions that seemed rather academic with little relevance to applications. But over time it developed into one of the key research areas for modern spintronic devices. This journey started off with investigating spin polarized charge currents, later focused on pure spin currents, and ultimately explored spin waves (magnons) as the potential carriers of spin information. Most of this work was performed in the Magnetic Films group of the Argonne National Laboratory, which for more than three decades used to be one of the world-leading places for magnetism research. • This manuscript chronicles research in the Magnetic Film group at Argonne. • Non-local transport enabled the exploration of pure spin currents. • Spin Hall effects morphed from academic curiosity to a key spintronics phenomenon. • Spin waves emerged as complementary types of spin currents. • Current open questions include structural chirality and orbital angular momentum.

The conventional approach to converting kraft lignin (KL) into hard carbons is to start with highly purified, low-ash KL feedstocks and then rely on slow, energy-intensive oxidative stabilization and added crosslinkers to keep melting and foaming associated thermal challenges under control. Herein, we deliberately invert this paradigm. Instead of starting with highly purified KL, we retain pulping inorganics and use them as catalytic centers for oxidative crosslinking and melt suppression of KL. Spherical KL microparticles (KL-MP) were recovered from softwood black liquor by membrane filtration and spray-drying steps, intentionally retaining inorganic sodium (Na) salts as well as organically bound Na in KL-MP, and were compared to acid-precipitated, low-ash reference KL (KL-REF). During thermo-oxidative pretreatment (250°C, 5°C/min) in air, KL-MP undergoes inorganic-catalyzed rapid oxidative crosslinking that converts thermoplastic lignin into a rigid network, whereas KL-REF softens, foams, and fuses. Experimental analysis identifies organically bound Na-phenoxide type species as key catalytic sites. Proton magnetic resonance thermal analysis and molecular dynamics simulations reveal strongly reduced segmental mobility and Na-driven ionic clusters acting as physical crosslinking points. After pretreatment, inorganics are removed by a washing step, and the crosslinked KL-MP is carbonized, yielding low-surface-area hard carbons that retain their initial micron size and spherical morphology. As Li-ion battery anodes, the derived hard carbon shows better electrochemical performance than carbons derived from KL-REF. Overall, the work shows how otherwise undesirable inorganic impurities can simplify thermal conversion of KL, with potential for diverse applications where particle size and shape are critical.

Growth rate induced modulation of perpendicular magnetic anisotropy and domain dynamics in ferrimagnetic TbFe thin film

Cooper-pair localization in the magnetic dynamics of a cuprate ladder

Spin-torque nano-oscillators (STNOs) are promising nanoscale microwave oscillators for applications in wireless communication and neuromorphic computing. Although simulations suggest that STNOs with tilted magnetic anisotropy (TMA) can deliver superior performance, experimental investigations-especially those employing TMA free layers-remain unreported. Here, we experimentally investigate nanocontact STNOs (NC-STNOs) incorporating a TMA free layer based on a [Co/Pd]/Cu/[Co/Ni]/NiFe multilayer structure. By integrating experimental measurements with micromagnetic simulations, we uncover rich magnetization dynamics that are inaccessible in conventional anisotropy systems. Notably, we observe the coexistence and transition between distinct dynamical modes, which give rise to multi-frequency microwave emission. In addition, we identify a unique droplet-like propagating spin-wave (PSW) mode that simultaneously exhibits characteristics of both magnetic droplets and PSW. Most importantly, this droplet-like PSW mode enables synchronization over significantly greater distances compared to perpendicular magnetic anisotropy (PMA)-based STNOs, highlighting its potential for large-scale mutual synchronization. These findings advance the understanding of magnetization dynamics in TMA systems and establish a pathway toward synchronized STNO arrays for practical applications.

This study investigates the impact of Er3+ and Zr4+ substitution on the glassy magnetic behaviour of the quasi-one-dimensional spin-chain compound Ca3Co2O6. Polycrystalline samples were synthesized using solid-state reaction methods, and structural characterization confirmed single-phase formation in the rhombohedral R c space group. Magnetic measurements revealed that glassy temperatures (Tg) shift with substitution: Er doping reduces Tg from 11.1 K to 9.2 K, weakening spin-glass behavior, while Zr doping increases Tg to 13.0 K, enhancing glassy characteristics. Magnetic relaxation studies at 8 K using the Weron function showed that Zr substitution increases the relaxation time (τ = 205 s), whereas Er substitution suppresses it (τ = 161 s). These findings demonstrate that chemical substitution at different sites effectively tunes the competing magnetic interactions and glassy dynamics in geometrically frustrated Ca3Co2O6.

Laser‐induced switching of magnetization between multiple magnetic states has tremendous potential for data recording and storage applications. As a nonthermal phenomenon, photo‐magnetic switching stands out from various discovered switching mechanisms with its unparalleled energy efficiency. Dielectric rare‐earth iron garnet cubic crystals, where it has been observed, enrich magnetization dynamics with high symmetry and complicated magnetic anisotropy landscape, enabling storage of multiple bits of information in a single magnetic domain. In this work we demonstrate methods to control the photo‐magnetic torque, which sets the magnetization into motion and eventually determines both its trajectory and destination. We use the formalism based on Landau–Lifshitz–Gilbert dynamics with an effective anisotropy field originating in the photo‐magnetism and analyze the methods to modify the torque sign and magnitude. In particular, we demonstrate how varying equilibrium magnetization, light polarization, and using plasmonic excitations in metal‐dielectric hybrids enable steady control of the photo‐magnetic dynamics, which is key for the multistate switching. Our work outlines promising directions for future research towards highly efficient magnetic recording at the nanoscale.

In quantum magnetic materials it is common to observe both static and dynamic lattice effects on the magnetic excitation spectrum. Less common is to find that the magnetic correlations have a significant impact on the phonon spectrum. Here we study the metal-organic material ( C 5 H 9 NH 3 ) 2 CuBr 4 (Cu-CPA), in which an explanation of the low-lying excitations depends crucially on a full understanding of both the spin and lattice subsystems. We report high-resolution neutron spectroscopy enabled by large, deuterated single crystals that reveal how both sectors are affected by the recently discovered structural phase transition. By measuring over several Brillouin zones, we disentangle the vibrational contribution to the spectrum in order to obtain an accurate estimate of the quasi-one-dimensional magnetic signal. The low-energy magnetic excitations are dominated by two gaps, Δ b = 0.41 meV and Δ a = 0.55 meV , which contribute with equal intensity ratios, confirming that Cu-CPA realizes a two-ladder spin Hamiltonian, and we deduce the magnetic interaction parameters of both ladders. The phonon spectrum contains highly localized modes at an anomalously low energy around 2 meV. For half of these modes, this characteristic frequency drops by approximately 5% as magnetic correlations become established with decreasing temperature, and we connect this apparent “elastomagnetic” behavior with the location and structure of the cyclopentylammonium rings.

ABSTRACT This paper takes the integrable Kuralay equations as the research object, aiming to derive various types of soliton solutions and explore the integrable motion of space curves induced by the equations, so as to support the research on nonlinear spin dynamics in the field of magnetic materials. In this paper, the unified ‐expansion method is used to systematically derive soliton solutions expressed by Jacobian elliptic functions. Through parameter degeneration (degenerating into hyperbolic function solutions when the modulus and trigonometric function solutions when ), the evolutionary relationship among different solutions is revealed. Eight types of soliton solutions are obtained in this paper, including periodic trigonometric function solutions, parabolic function solutions, singular solutions, and M‐shaped/W‐shaped solitons (corresponding to Figures 1–8). The parameter configurations and 2D/3D graphical characteristics of each solution are clarified (e.g., kink waves show unidirectional step‐like transitions, and M‐shaped bright waves possess symmetric double peaks). All solitons have clear boundaries without diffusion. For numerical verification, the fourth‐order Runge‐Kutta method combined with Richardson extrapolation is adopted, reducing the calculation error from to . In addition, phase portrait, bifurcation, and initial condition sensitivity analyses are supplemented, and the stability of equilibrium points is classified by the eigenvalues of the Jacobian matrix. In terms of physical implications, the soliton solutions are deeply associated with magnetic spin systems. For instance, kink waves correspond to the migration of spin domain walls, supporting the reading and writing operations of magnetic storage; M‐shaped/W‐shaped solitons contribute to the realization of multistate and high‐density storage. The quantitative influences of parameters on the low‐power consumption and high‐capacity performance of devices are clarified, providing theoretical support and practical guidance for the research on nonlinear spin dynamics and the design of magnetic storage and magneto‐optical modulation devices.

Abstract Single-crystalline full-Heusler alloy Co 2 MnAl film with B2 structure was prepared on MgO(100) substrate grown by pulsed laser deposition (PLD), and its anomalous Hall effect (AHE) as well as ultrafast dynamics was investigated. The experimental results indicate that the enhanced chemical ordering of the film can weaken the influence of skew scattering mechanisms on transport, exhibiting a pronounced intrinsic Berry curvature contribution to the AHE. The variation of carrier concentration with temperature obtained by AHE is reasonably analyzed using the Fermi-Dirac distribution function. Additionally, THz emission can generally be governed by mechanisms such as AHE-driven currents and ultrafast laser-induced demagnetization (UDM); here, the observed THz emission is attributed primarily to UDM. The intensity of the electric field associated with the radiation pulses is linearly related to the pump fluence, and the obtained THz emission spectra can be utilized to studies of magnetic dynamics on Co 2 MnAl. These results are valuable to deepen understanding of THz electromagnetic emission and promote practical applications in spintronics, THz functional devices, and emerging information-storage technologies.

Human α-synuclein is an intrinsically disordered protein concentrated at presynaptic terminals and strongly linked to Parkinson's disease and other synucleinopathies. Its dynamic C-terminal region mediates interactions with small molecules and metal ions. Here, we used high-resolution nuclear magnetic resonance spectroscopy (NMR) and molecular dynamics (MD) simulations to characterize interactions between the C-terminal α-synuclein construct, the small molecule fasudil, and calcium ions. NMR data show that fasudil and Ca2+ bind preferentially to overlapping regions enriched in alternating tyrosine and acidic residues while preserving the protein's disordered nature. Side-chain-resolved spectra indicate distinct driving forces for fasudil and calcium binding. MD simulations reveal that Ca2+ modifies the local electrostatic environment, decreasing fasudil interaction frequency through electrostatic screening and steric effects. Despite this, fasudil retains dynamic, reversible contacts with key tyrosine residues. Overall, exposed α-synuclein conformations allow simultaneous, ligand-specific interactions, highlighting side-chain hotspots governing binding in Ca2+-rich conditions.

The magnetization dynamics induced by the surface acoustic wave: Model, simulation, and experiment

Capturing the dynamic variations of nanoscale viscosity within biological fluids is pivotal for deciphering the mechanisms of critical physiological and pathological processes, notably blood coagulation. However, this endeavor remains challenging due to the limitations of conventional techniques. Standard assays relying on bulk optical or rheological measurements lack the spatial resolution required for nanoscale viscosity analysis, failing to distinguish cascade processes in complex coagulation reactions. We present an optomagnetic nanorelaxometry platform that probes nanoscale viscosity in real time through analysis of magnetic nanoparticles' Brownian relaxation dynamics. Requiring a sample volume of 50 μL, the platform demonstrated quantitative accuracy in glycerol solutions and successfully tracked dynamic viscosity changes during collagen gelation. Most notably, during platelet-rich plasma coagulation, our platform revealed a nonmonotonic viscosity profile inaccessible to conventional assays, suggesting a novel methodological perspective on coagulation mechanisms. Evaluation with clinical anticoagulants and a thrombolytic agent further confirmed its practical utility, underscoring the platform's potential for pharmacological screening and point-of-care coagulation monitoring with nanoscale resolution.

Comprehensive study of 3D liquid flow fields in additive manufactured structures for SMART reactors using large-scale vertical magnetic resonance imaging and computational fluid dynamics

École Nationale Supérieure de Chimie de Paris, ParisTech, France 9–12 December 2025 The Conference on Research and Innovations in Science and Technology of Material 2025 (CRISTMas 2025) was held from 9 to 12 December 2025 at École Nationale Supérieure de Chimie de Paris, Paris, France. Organised by the STEMM Global Scientific Society, CRISTMas 2025 brought together researchers, engineers, and industry representatives to discuss emerging directions in materials science, advanced physical systems, functional materials engineering, and heritage technologies. The conference provided an interdisciplinary platform covering fundamental and applied research across electromagnetic and nonlinear systems, photonic and quantum platforms, heritage science and protective technologies, and advanced functional materials. Contributions addressed topics ranging from magnetic field engineering and nonlinear circuit dynamics to topological photonics, optomechanical systems, digital heritage frameworks, sustainable polymers, graphene-enabled surface technologies, and advanced materials interfaces. CRISTMas 2025 continued its mission of fostering dialogue between fundamental science and practical implementation, supporting the translation of advanced materials research into engineering solutions and societal applications. The proceedings reflect this interdisciplinary character and present peer-reviewed contributions that demonstrate both scientific rigor and applied relevance. List of Editorial Board, Scientific and Organising Committee are available in this PDF.

Hemodynamic evaluation using four-dimensional flow magnetic resonance imaging or computational fluid dynamics can identify a high-risk phenotype in Kommerell's diverticulum, which is characterized by intradiverticular vortex formation, low wall shear stress, and elevated oscillatory shear index (OSI). This functional assessment provides crucial risk stratification beyond anatomical size, as a high OSI may pinpoint intimal vulnerability sites and potential dissection entry.

Complex frustrated magnetic behaviors dynamics in multiphase iron-containing aluminosilicate glass system

Abstract Magnetic clouds (MCs) are large-scale magnetic structures in the solar wind whose internal physical processes remain only partially understood. In this work, we present an extended analytical model of MCs that simultaneously describes the magnetic field, plasma pressure, current density, and induced electric field during the spacecraft crossing of the structure. Building upon previous non-force-free formulations, the model incorporates the induced electric field as an additional physical constraint linking magnetic and plasma dynamics. The model is applied to a set of representative MC events observed by the Wind spacecraft. By fitting multiple observables simultaneously, the approach reduces parameter correlations and leads to more stable determinations of the flux-rope axis orientation compared to earlier versions based solely on magnetic field measurements. The inclusion of plasma-related quantities allows departures from idealized force-free configurations to be identified and provides additional insight into the internal topology and evolution of MCs. The comparison of several example events illustrates both the capabilities and limitations of the model, showing that its performance degrades in cases exhibiting enhanced short-timescale variability or boundary interactions. Overall, the present formulation provides a more physically consistent framework for interpreting in situ observations of MCs in the interplanetary medium.

The ultrafast magnetization dynamics of an epitaxial Fe/CoO bilayer on Ag(001) is examined in an element-resolved way by resonant soft-x-ray reflectivity. The transient magnetic linear dichroism at the Co L_{2} edge and the magnetic circular dichroism at the Fe L_{3} edge measured in reflection in a pump-probe experiment with 120fs temporal resolution show the loss of antiferromagnetic and ferromagnetic order in CoO and Fe, respectively, both within 300fs after excitation with 60fs light pulses of 800 and 400nm wavelengths. A comparison to spin-dynamics simulations using an atomistic spin model shows that direct energy transfer from the laser-excited electrons in Fe to the magnetic moments in CoO provides the dominant demagnetization channel in the case of 800-nm excitation.

Abstract In permanent magnet synchronous machine (PMSM)-based servo systems, the intricate interplay of electrical and magnetic dynamics poses many practical challenges, particularly in high-frequency position tracking scenarios. Inappropriate control methods employed with the PMSM may lead to unacceptable phase lags and even jeopardize the connected precision machining or laser processing devices. This article establishes a high-frequency position tracking control framework for PMSM-based servo systems considering dynamic load identification. Therein, a reduced-order generalized proportional-integral observer-based composite control strategy is developed for stator current regulation, aiming at improving the transient/steady-state performance and anti-disturbance capability. An adaptive quasi-proportional-resonant control and a disturbance observer are proposed for position and speed regulations, respectively, enabling the rapid tracking of high-frequency sinusoidal references, as well as the accurate identification of load conditions of the PMSM. The stability of these algorithms is theoretically verified by accommodating the model of the servo system. The superiority of the proposed high-frequency position tracking control framework considering various operating scenarios of the system is verified by diversified simulations and hardware-in-the-loop-based experiments.