Engineered assemblies of interacting magnetic elements—magnetic metamaterials—provide a powerful route to tailor collective magnetic order and dynamics. By structuring matter at the mesoscale, they bridge atomic magnetism and macroscopic functionality, enabling emergent behaviour inaccessible in conventional materials. However, realizing large-area metamaterials that combine high morphological uniformity with intrinsic long-range order has remained challenging, largely due to the structural disorder inherent to lithographic fabrication. Here we demonstrate a scalable route to structurally and magnetically coherent metamaterials by embedding iron-ions to form mesospins within a non-magnetic thin film palladium host matrix. Using controlled implantation, we realize morphologically uniform arrays that spontaneously develop extended antiferromagnetic order in the as-fabricated state—without the need of external annealing or field cycling. Resonant X-ray scattering and microscopy reveal sharp magnetic Bragg peaks modulated by the mesospin form factor, evidencing long-range antiferromagnetic order coupled to structural coherence. This embedded architecture establishes a platform for exploring coherent spin–photon interactions and functional X-ray scattering in magnetic metamaterials free from lithographic topography and disorder.

Magnetoelectric materials enable low-power memory devices by leveraging the electric control of magnetization. The discovery of ferroelectricity in doped hafnia has unlocked further opportunities since the distinct ferroelectric switching mechanism in this material can enable robust and multilevel modulation of magnetization by electric field, if combined with appropriate magnetic materials. Here, we demonstrate a 5% electric field-induced modulation of the saturation magnetization in a cobalt layer, driven by ferroelectric switching of an adjacent epitaxial La(1%):Hf0.5Zr0.5O2 film. Dichroic imaging with synchrotron radiation confirms that ferroelectric switching induces a magnetic change. We show that the response time is faster than 500 ns (limited by the setup time resolution threshold) and that energy consumption is 6 nJ. This low energy consumption is mainly enabled by the absence of relevant leakage current contribution (10 nA/cm(2) at 500 mV). The found response time and energy-efficient behavior point to the presence of an electronically driven modulation of magnetism (i.e., conventional magnetoelectric effects), which is confirmed by theoretical calculations and compositional analysis. Additionally, a multilevel magnetoelectric response is observed, enabling neuromorphic-like behavior. The demonstration of magnetoelectric coupling in a system based on CMOS-compatible materials offers a viable route toward the development of low-power beyond von-Neumann technologies.

Artificial spin ice (ASI) are metamaterials composed of interacting nanomagnets. Although ASI hold promise for low-power computing, the ability to transmit information through these two-dimensional systems has been limited. Inspired by non-reciprocal transport in nature, we develop a framework for non-reciprocal influence between nanomagnets. Using the framework we discover a family of ASI geometries with inherent directionality. Directional ASI have the property that, when driven by an external field protocol, domains grow and reverse in the same direction, illustrating an emergent non-reciprocity of the system. Combining growth and reversal results in unidirectional domain movement through the metamaterial. We focus on one member of the directional ASI family, and demonstrate unidirectional domain growth experimentally. Furthermore, we show that the direction of growth is reconfigurable by tuning the external field strengths. Finally, we demonstrate how the directionality of the system significantly improves memory capabilities in a reservoir computing framework. Our work is the first demonstration of an ASI with inherent directionality, offering a magnetic computing platform that combines memory and computation within a single neuromorphic substrate.

Controlling domain walls in cylindrical geometries through energy-efficient spintronic methods is a key challenge for advancing future three dimmensional (3D) nanotechnologies. Here we used the X-ray Magnetic Circular Dichroism combined with Photoemission Electron Microscopy (XMCD-PEEM) technique to investigate domain wall dynamics in cylindrical magnetic nanowires under nanosecond current pulses. We found that small current densities (similar to 4 & times; 101 1 A/m2) effectively move domain walls and saturate the nanowire. Surprisingly, when the current density is further increased, the domain walls are not expelled from the nanowire. Instead, they rebound from the nanowire ends, with the rebound distance increasing as the pulse duration increases. Our modeling reveals that spin-transfer torque dominates at lower currents, whereas at higher currents, it competes with a thermal gradient which pushes domain walls toward the nanowire center. These results underline the importance of thermal effects in cylindrical geometries and their implications for the design of robust spintronic devices.

The exploration of two-dimensional (2D) van der Waals ferromagnets has revealed intriguing magnetic properties with significant potential for spintronics applications. In this study, we examine the magnetic properties of Co-doped Fe5GeTe2 using x-ray photoemission electron microscopy (XPEEM) and x-ray magnetic circular dichroism (XMCD), complemented by density functional theory calculations. Our XPEEM measurements reveal that the Curie temperature (T-C) of a bilayer of (CoxFe (1-x))( 5-delta)GeTe2 (with x = 0.28) reaches similar to 300 K-a notable enhancement over most 2D ferromagnets in the ultrathin limit. Interestingly, the T(C )shows only a small dependence on film thickness (bulk T-C approximate to 340 K), in line with the observed in-plane (IP) magnetic anisotropy and robust IP exchange coupling. XMCD measurements indicate that the spin moments for both Fe and Co are significantly reduced compared to the theoretical values. These insights highlight the potential of Co-doped Fe5GeTe2 for stable, high-temperature ferromagnetic applications in 2D materials.

Topological defects, or singularities, play a key role in the statics and dynamics of complex systems. In magnetism, Bloch point singularities represent point defects that mediate the nucleation of textures such as skyrmions and hopfions. While these textures are typically stabilised in chiral magnets, the influence of chirality and symmetry breaking on Bloch point singularities remains relatively unexplored. Here, we harness advanced three-dimensional nanofabrication to explore the influence of symmetry breaking on Bloch point textures by introducing controlled nano-curvature in a ferromagnetic nanowire. Combining X-ray magnetic microscopy with the application of in situ magnetic fields, we demonstrate that Bloch point singularity-containing domain walls are stabilised in straight regions of the sample, and determine that curvature can be used to tune the energy landscape of the Bloch points. Not only are we able to pattern pinning points but, by controlling the gradient of curvature, we define asymmetric potential wells to realise a robust Bloch point texture shift-register with non-reciprocal behaviour. These insights into the influence of symmetry on singularities offer a route to the controlled nucleation and propagation of topological textures, providing opportunities for logic and computing devices.

The interaction between surface acoustic waves and magnetization offers an efficient route for electrically controlling magnetic states. Here, we demonstrate the excitation of magnetoacoustic waves in galfenol thin films with a 28 at. % gallium composition, corresponding to the second magnetostrictive peak in bulk samples. We quantify the amplitude of the induced magnetization oscillations using magnetic imaging in an x-ray photoelectron microscope and estimate the dynamic magnetoelastic constants through micromagnetic simulations. Our findings demonstrate the potential of galfenol thin films for magnonic applications and reveal that, despite strong magnetoelastic coupling, magnetic interactions and spin-wave dispersion relations significantly influence the overall amplitude of magnetoacoustic waves.

Surface Acoustic Waves (SAW) have been used in spintronic applications to decrease the magnetic field or the electric current required to act on the magnetization. A common belief is that a SAW alone cannot achieve a directed magnetic switching in a device without an assisting magnetic field or electric current. In this work, we demonstrate magnetic domain wall motion driven solely by an acoustic wave. Using XMCD-PEEM, we show extensive evidence of SAW-induced and field-free magnetic domain wall motion (DW) in the direction of the wave propagation. Our micromagnetic simulations reveal a mechanism that allows the SAW to transfer linear momentum to the DW. Experimentally, the largest DW average velocity measured was 12 m/s, although our simulations predict that velocities in the range of 100 m/s could be attained. This new mechanism opens the door to designing innovative spintronic devices where the magnetization can be controlled exclusively by an acoustic wave.

We have studied the (110) surface of Fe $$_{3}$$ O $$_{4}$$ single crystals by means of X-ray Photoemission Electron Microscopy (PEEM) and Low-Energy Electron Microscopy (LEEM) to characterize its structural and magnetic properties. After sputtering and annealing a well defined surface was achieved. This preparation method resulted in a one-dimensional reconstruction formed by rows aligned in the [001] direction. By acquiring X-ray magnetic circular dichroism PEEM images at various azimuthal angles, the vector magnetization map of the (110) surface was obtained. Domains were observed with their magnetization aligned along the two $$\langle 111\rangle$$ type bulk easy axes which are in the (110) surface plane, featuring 180 $$^{\circ }$$ , 109 $$^{\circ }$$ , and 71 $$^{\circ }$$ domain walls. The domain walls are of Néel type. Using the sum rules we estimated an iron spin and orbital magnetic moment of 3.4 $$\mu _B$$ and 0.6 $$\mu _B$$ respectively for the reconstructed surface. At the oxygen K edge we observe dichroic contrast of close to 1%, which is reversed relative of the contrast detected from octahedral iron in the L $$_3$$ edge.

We study experimentally the impact of the additive fabrication method on the magnetic properties of Fe^+-implanted Pd square artificial spin ice lattices. Our findings show that the lattices exhibit a higher ordering temperature than their continuous film counterparts. This behavior is attributed to the additive fabrication process, which induces an inhomogeneous Fe concentration within the lattice building blocks. Moreover, the implantation process creates a magnetic depth profile, enabling temperature-dependent tunability of the magnetic thickness. These additional internal degrees of freedom broaden the design possibilities for magnetic metamaterials, allowing precise fine-tuning of their static and dynamic properties to achieve complex and customizable behaviors.

Inverse oxide-metal model catalysts can show superior activity and selectivity compared with the traditional supported metal-oxide architecture, commonly attributed to the synergistic overlayer-support interaction. We have investigated the growth and redox properties of ceria nanoislands grown on Au(111) between 700 and 890 °C, which yields the CeO2-Au(111) model catalyst system. We have observed a distinct correlation between deposition temperature, structural order, and oxide composition through low-energy electron microscopy, low-energy electron diffraction, intensity-voltage curves, and X-ray absorption spectroscopy. Improved structural order and thermal stability of the oxide have been achieved by increasing the oxygen chemical potential at the substrate surface using reactive oxygen (O/O2) instead of molecular O2 during growth. In situ characterization under reducing (H2) and oxidizing atmospheres (O2, CO2) indicates an irreversible loss of structural order and redox activity at high reduction temperatures, while moderate temperatures result in partial decomposition of the ceria nanoislands (Ce3+/Ce4+) to metallic cerium (Ce0). The weak interaction between Au(111) and CeO x would facilitate its reduction to the Ce0 metallic state, especially considering the comparatively strong interaction between Ce0 and Au0. Besides, the higher reactivity of atomic oxygen promotes a stronger interaction between the gold and oxide islands during the nucleation process, explaining the improved stability. Thus, we propose that by driving the nucleation and growth of the ceria/Au system in a highly oxidizing regime, novel chemical properties can be obtained.

The expansion of nanomagnetism to the third dimension leads to phenomena such as curvature-induced magnetochirality and anisotropy, which can significantly influence the behavior of magnetic textures. One of the most promising systems is the magnetic nanotube - where intrinsic curvature effects are present. However, studies of magnetic nanotubes remain limited to straight systems, and little is known about the influence of 3D geometries. In this work, three dimensional (3D) complex-shaped nanotubes are fabricated by combining nanoprinting with the conformal deposition of magnetic films. Specifically, 3D conductive non-magnetic tungsten scaffolds are fabricated using focused electron beam induced deposition and subsequently coated with a nickel magnetic shell, resulting in complex-shaped magnetic nanotubes whose geometry can be controlled by tuning the electron-beam parameters and electrodeposition conditions. Performing X-ray microscopy revealed that nanotubes of various geometries host a vortex-like azimuthal state, and that the energy landscape of the magnetic configuration can be tailored geometrically. Specifically, the pinning of magnetic domain walls at curved vertices is observed experimentally and confirmed with micromagnetic simulations, offering geometrical control of magnetic configurations in nanotube architectures. This approach provides a new pathway to fabricate and study complex 3D core-shell magnetic structures, facilitating experimental investigations of their fundamental properties, key for the next-generation of spintronic devices.

The intercalation of a ferromagnet (FM) under graphene (Gr) allows the preparation of flat, highly perfect hybrid Gr/FM/Heavy metal (HM) heterostructures with unique properties. The presence of Gr promotes a layer-by-layer growth of the FM underneath, resulting in atomically flat interfaces with tunable interfacial interactions. In this work, we study the mechanisms of Fe intercalation in Gr/Pt(1 1 1) and Gr/Ir(1 1 1) grown onto insulating oxide crystals. Experimental results reveal the epitaxial growth of high quality FCC Fe layers intercalated underneath Gr, with abrupt interfaces, in-plane magnetization and a reduction of the graphene work function due to Gr/Fe interaction.

Chiral magnetic textures are key for the development of modern spintronic devices. In multilayered thin films, these are typically stabilized via the interfacial intralayer Dzyaloshinskii-Moriya interaction (DMI). Additionally, it has been recently observed that DMI may also promote vector spin chirality along the third dimension, coupling spins in different magnetic layers via nonmagnetic spacer layers, an effect referred to as interlayer DMI (IL-DMI). This interaction holds promise for 3D nanomagnetism, from the creation of 3D spin structures such as hopfions to new forms of magnetic functionality in the vertical direction via remote control of chiral spin states. In this work, we provide direct experimental evidence that the in-plane vector spin chirality of magnetic textures within a ferromagnetic layer can be controlled via the net out-of-plane spin configuration of an adjacent one. Both ferromagnetic layers form part of a synthetic antiferromagnet, previously shown to have IL-DMI. This in-plane vector chirality dependence on the out-of-plane configuration of another layer implies that the overall scalar spin chirality is preserved when computed across layers. We draw these conclusions from a combination of magnetic x-ray scattering and imaging experiments, complemented by various simulations. These findings thus uncover a type of chiral interlayer interactions, which can lead to the formation of intricate spin states across a metallic interface, demonstrating other ways to control magnetic chirality in three dimensions.

The study investigates the manipulation of the magnetic anisotropy in a thick (1 μm) Ni 90 Fe 10 layer electrodeposited on a ferroelectric BaTiO 3 (001) substrate, using a combination of Magneto-optical Kerr Effect, Photoemission Electron Microscopy with X-ray circular magnetic dichroism and X-ray diffraction. In the as-grown state, the system shows weak perpendicular magnetic anisotropy and characteristic stripe domains. Upon out-of-plane electrical poling of the BaTiO3 substrate, the magnetic anisotropy switches to in-plane with a strong uniaxial behavior. The perpendicular magnetic anisotropy can be recovered by mild thermal annealing above the BaTiO 3 tetragonal to cubic phase transition and can be cycled by repeated electrical poling/thermal annealing. This method opens the path to a reversible control of the magnetic anisotropy in hybrid lead-free magnetoelectric Ni 90 Fe 10 /BaTiO 3 heterostructures from perpendicular to in-plane.

We investigate the interfacial spin structure of prototypical room-temperature antiferromagnet NiO, epitaxially grown on Fe3O4(111)/Ru(0001). The heterostructures were fabricated using high-temperature oxygen-assisted molecular beam epitaxy on a Ru single-crystal substrate. A comprehensive structural characterization was carried out by low-energy electron microscopy and diffraction, while chemical and magnetic properties were probed using photoemission electron microscopy combined with synchrotron radiation. Specifically, X-ray absorption spectroscopy and X-ray magnetic circular/linear dichroism enabled nanoscale analysis of the magnetic ordering. Although bulk NiO is antiferromagnetic and exhibits no net magnetization, hence showing no circular dichroism, interfacial interactions at the Fe3O4/NiO boundary can significantly influence the magnetic domain configuration in NiO, leading to emergent interfacial magnetic behavior. By resolving the spin axis orientation of NiO with nanometer precision and correlating it with the ferrimagnetic domain structure of Fe3O4, we provide new insight into the interfacial coupling mechanisms.

BaFe12O19 (BFO) thin films have been grown on Si(100) substrates by magnetron sputtering from previously synthesized ceramic BFO targets and have been compositionally and structurally characterized. Films grow with the c-axis orientation and magnetization direction parallel to the sample plane. In addition, the magnetic coupling between the BFO film and a deposited cobalt overlayer was studied. Images of X-ray magnetic circular dichroism in photoemission microscopy show magnetic regions in the BFO layer with domain sizes of several micrometers and others without magnetic contrast, the latter attributed to the presence of hematite. Magnetic domains in the Co overlayer show no significant correlations with those in the BFO film, pointing to a negligible magnetic coupling. (c) 2025 The Author(s). Published by Elsevier Espana, S.L.U. on behalf of SECV. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/ by-nc-nd/4.0/).

We investigate the design of magnetic ordering in one-dimensional mesoscopic magnetic Ising chains by modulating long-range interactions. These interactions are affected by geometrical modifications to the chain, which adjust the energy hierarchy and the resulting magnetic ground states. Consequently, the magnetic ordering can be tuned between antiferromagnetic and dimer antiferromagnetic phases. These phases are experimentally observed in chains fabricated using both conventional electron-beam lithography and ion implantation techniques, demonstrating the feasibility of controlling magnetic properties at the mesoscale. The ability of attaining these magnetic structures by thermal annealing, underlines the potential of using such systems instead of simulated annealers in tackling combinatorial optimization tasks.

This study integrates multiple microscopy techniques to investigate the effect of introducing axial compositional gradients on the magnetic properties of Fe-Ni ferromagnetic nanowires. We study the chemical structure of the nanowires using photoemission electron microscopy and transmission (X-ray and electron) microscopy. We explore the magnetic properties through magnetic force microscopy, complemented by micromagnetic simulations, and we characterize the 3D magnetization vector by measuring magnetic circular dichroism using X-ray microscopies. We observe that variations in the Fe/Ni ratio induce localized magnetic curling in Fe-rich regions, while Ni-rich segments predominantly exhibit axial magnetization, demonstrating how compositional gradients can control magnetic domain configurations on the nanoscale. Our results highlight the value of multimodal imaging for uncovering the interplay among structural, chemical, and magnetic properties in complex nanostructures. These findings represent a significant step toward the manipulation of magnetic domains in nanowires, which is essential for future devices based on 3D nanomagnetic architectures.