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Recently resynthesized FeNbTe2 has been confirmed to exhibit ferromagnetism. Using first-principles methods, we investigate the magnetic properties of two-dimensional FeXZ2 (X = Nb, Ta; Z = S, Se, Te) compounds, including their non-centrosymmetric Janus counterparts. These materials are found to be energetically, dynamically, thermally, and mechanically stable, indicating that FeNbTe2 can be exfoliated and that new related compounds could be realized experimentally. Analysis of hopping parameters reveals that nearest-neighbor magnetic interactions are primarily direct, while second-nearest and more distant interactions are mediated by chalcogen atoms. Despite their smaller magnitude, second-nearest interactions play a decisive role in magnetic ordering. We identify canted magnetic anisotropy with strong magnetocrystalline anisotropy energy and easy-axis tilts of up to 41 degrees, an uncommon feature favorable for spintronics. Monte Carlo simulations yield Curie temperatures below room temperature, while micromagnetic simulations predict that Janus FeNbSeTe can host zero-field N & eacute;el-type skyrmions, making it a promising target for experiments.

Magnetic hopfions are 3D topological solitons - knotted, vortex-like spin configurations. In chiral magnets, hopfions can appear as isolated structures or they can be linked to skyrmion strings. Previous studies employed a sophisticated protocol and a special sample geometry to nucleate such hopfions linked to one or a few skyrmion strings. Here, we introduce an electric-current-assisted nucleation protocol that is simple and independent of the sample shape and size. The resulting hopfions exhibit extraordinary stability in the presence of both positive and negative magnetic fields, in perfect agreement with micromagnetic simulations. We also present a comprehensive framework for classifying hopfions, skyrmions, and merons by deriving the corresponding homotopy group.

Bismuth-based compounds, such as Bi1(-x)Sb(x) or Bi2Te3, have outstanding electronic properties especially for advanced quantum devices. However, the potential of low-dimensional group V-Bi materials is largely undetermined. Here, we report the experimental realization of a two-dimensional (2D) BiAs layer with giant Rashba spin splitting, grown on an InAs(111)B substrate via molecular beam epitaxy. ARPES reveals the emergence of a prominent M-shaped band structure and a distinct electron pocket at the Fermi level. DFT, complemented by synchrotron-based XPS, LEED, and STM, confirms strong spin-orbit coupling and a giant Rashba coefficient of these electronic states. An As overlayer, remaining from the fabrication process, preserves a structural shift between substrate and BiAs layer, essential for the Rashba splitting, while preventing undesirable reconstruction. This indicates how well-known capping techniques can stabilize new 2D compounds with interesting electronic structures, especially BiAs, a promising candidate to open possibilities for next-generation spintronic devices and field-effect transistors.

High-pressure (HP) electrical resistivity measurements of superconducting quasi-skutterudite Y5Rh6Sn18 single crystals were conducted up to 10.7 GPa using a diamond anvil pressure cell. Additionally, HP synchrotron X-ray powder diffraction (XRPD) studies were performed on Y5Rh6Sn18 up to 8 GPa and Sc5Rh6Sn18 up to 11.7 GPa, along with HP Raman spectroscopy. At ambient conditions, the Y5Rh6Sn18 single crystal shows an onset 3.60 K, which increases to a maximum of 3.94 K at 7.89 GPa. Beyond this pressure, further increases lead to a slight decline in Tc. Furthermore, the bad metal nature of the Y5Rh6Sn18 single crystal is suppressed by external pressure, with the residual resistivity ratio (RRR) value increasing from 0.77 to 0.92. The activation energy for electric conduction (Ea) decreases from 2.74 meV at 0.62 GPa to 0.39 meV at 10.65 GPa, indicating enhanced metallic behaviour. Additionally, four Raman vibrational modes are observed, which exhibit a smooth blue shift with increasing pressure up to 9.6 GPa, similar to that of its sister compound Sc5Rh6Sn18. Both Y5Rh6Sn18 and Sc5Rh6Sn18 crystallize in the tetragonal I41/acd space group. With increasing external pressure up to 7 GPa, these compounds exhibit a smooth reduction in unit-cell volume without any structural phase transitions, as described by a second-order Birch-Murnaghan equation of state. Above 7 GPa, Sc5Rh6Sn18 also shows an upturn in both lattice parameters a and c and unit cell volume, while an upturn in only the lattice parameter c (and consequently on unit cell volume) is observed for Y5Rh6Sn18 at 7 GPa. The deviation in the lattice parameter at higher pressure in Y5Rh6Sn18 seems to correlate with the observed decline in Tc with pressure. First-principles calculations under pressure reveal a moderate increase in the density of states (DOS) up to ~ 10 GPa, followed by a slight decrease for higher pressures, a trend which is similar to the observed critical temperature. Furthermore, from theory it is clear that the structure remains stable up to approximately 30 GPa.

We examine the relation between the quantum Landau-Lifshitz equation (q-LL) [Wieser, Phys. Rev. Lett. 110, 147201 (2013)] and quantum Landau-Lifshitz-Gilbert equation (q-LLG) [Liu et al., Phys. Rev. Lett. 133, 266704 (2024)], two nonlinear purity preserving master equations that extend classical atomistic spin dynamics into the quantum regime. While the classical LL and LLG counterparts for any number of spins are known to be equivalent, i.e., give identical spin trajectories up to a rescaling of the time parameter, the quantum formulations are equivalent only in certain cases, such as for pure states or for arbitrary single spin-½ states. Here, we demonstrate that this equivalence breaks down even at the level of a single spin, provided s≥1. Focusing on a spin-1 particle in an anisotropic crystal field, we show that the q-LL and q-LLG equations generate inequivalent time evolution. We introduce temporal rescaling misfits that quantify the inequivalence of the two types of dynamics. Although our results highlight fundamental differences in dissipation mechanisms encoded in these equations, the resulting trajectories remain qualitatively similar for this system.

Controlled generation of topological spin textures, such as merons and their bound state, the bimerons, is essential for advancing spintronic technologies and elucidating soliton physics in condensed matter. Using in situ Lorentz transmission electron microscopy coupled with femtosecond laser pulse, we demonstrate the creation of two distinct Bloch-type bimeron states in chiral magnet Co8Zn8Mn4 thin plates at room temperature. Magnetic imaging and micromagnetic simulations reveal that bimeron density varies with applied magnetic field strength, enabling dynamic topological control. We further establish that the topological classification of laser-generated bimerons is invariant with specimen thickness. Field-driven reversible transformations between elongated and circular bimeron morphologies are observed, governed by the competition of Zeeman energy and magnetic shape anisotropy. Micromagnetic simulations quantitatively reproduce these metastable states, validating a unified meron-skyrmion topological framework. This work establishes a single-pulse protocol for optical manipulation of topological spin textures.

Magnetic solitons have recently attracted significant attention due to their intricate physical properties and potential applications in information processing. The majority of the studies in this field, however, are focused on a particular type of solitons known as skyrmions, characterised by a unit topological charge. Here, we present a shifted magnetic bilayer that can demonstrate magnetic solitons with arbitrary large topological charges. These configurations, which we call linked skyrmions, consist of multiple skyrmions linked together with topological point defects. These topological point defects, termed as anti-aligned points, originate from the mutually orthogonal Dzyaloshinskii-Moriya interaction in two different layers. By tuning the interlayer exchange coupling and the external magnetic field, one can also achieve different ground states in this bilayer. Additionally, the system also demonstrates conventional skyrmion-bags and k pi-skyrmions. Finally we propose a suitable material candidate where these magnetic configurations can be realised. Our findings, thus, can provide a way to achieve solitons with large topological charge and realise them in realistic systems.

Shake-up phenomena, rooted in the sudden approximation and many-body quantum dynamics, unveil critical characteristics of quantum systems, with wide-ranging applications in molecular spectroscopy and electronic structure studies. Here, this principle is extended to magnetic systems, and magnon shake-up structures and their relevance in generating and sensing magnon-magnon entanglement are demonstrated. This not only reveals new insights into shake-up phenomena and quantum magnetism but also paves the way for new opportunities in quantum technologies.

In this work, we present the first magnetization measurements of DyCo₅ single crystals in magnetic fields up to 14 T, spanning a temperature range up to 600 K. Our investigation reveals several unique features, including a significant magnetization anisotropy and an observed minimum in spontaneous magnetization near the compensation point, phenomena not previously reported. This work also uncovers the complex magnetic behavior of DyCo₅, with a pronounced interplay between the Dy and Co sublattices, each exhibiting distinct temperature-dependent magnetic properties. The combination of dynamical mean-field theory (DMFT), atomistic spin-dynamics (ASD) simulations, and the Effective Spin Model (ESM) for rare-earth compounds successfully explains the experimental data across both low and high temperatures. Our theoretical approach not only explains the observed magnetic anisotropy and the behavior near the compensation temperature but also successfully reproduces key experimental features such as the saturation behavior at high fields and the evolution of the magnetic moment at different temperatures.

A major challenge in condensed matter physics is integrating topological phenomena with correlated electron physics to leverage both types of states for next-generation quantum devices. Metal-insulator transitions are central to bridging these two domains while simultaneously serving as on-off switches for electronic states. Here, we demonstrate how the prototypical material of K₂Cr₈O₁₆ undergoes a ferromagnetic metal-insulator transition accompanied by a change in band topology. Through inelastic x-ray and neutron scattering experiments combined with first-principles theoretical calculations, we show that this transition is not driven by a Peierls mechanism, given the lack of phonon softening. Instead, we establish the transition as a topological metal-insulator transition within the ferromagnetic phase with potential axionic properties, where electron correlations play a key role in stabilizing the insulating state. These results reveal how a metal-insulator transition provides a pathway through which magnetism, topology, and electronic correlations interact.