Researchers at Carnegie Mellon University, Boston College, the University of California, Los Angeles, the Air Force Research Laboratory, Kansas State University, Japan's National Institute for Materials Science, and Harvard University have experimentally demonstrated an in-plane anomalous Hall effect (AHE) in a low-dimensional heterostructure, overturning the long-held assumption that the anomalous Hall response can only be driven by a material's out-of-plane magnetization.

The Hall effect, first observed in 1879, has served for well over a century as a core tool for probing a material's electronic properties: applying a magnetic field perpendicular to a conducting material deflects moving charges and produces a measurable voltage, revealing whether current is carried by positive or negative charge carriers and how many are flowing. In magnetic materials, the anomalous Hall effect adds a magnetization-dependent contribution to that signal, but symmetry constraints have generally required that response to scale with the out-of-plane component of magnetization alone. An in-plane version of the effect had been theoretically proposed but never demonstrated, largely because it requires a magnetic material with a very specific, reduced crystalline symmetry that is difficult to realize.

Researchers at Shenzhen University, the Japan Atomic Energy Agency, the National Institutes for Quantum Science and Technology (QST), the University of Tokyo, the University of Science and Technology of China, Xi'an Jiaotong University, Shenzhen Technology University (SZTU), and The Hong Kong Polytechnic University, have provided the first element-resolved confirmation of intrinsic carbon ferromagnetism at room temperature in a bulk, wafer-scale material. The result, obtained in a hyper-porous graphene network (HGN) grown across a 2-inch silicon wafer, adds carbon to the small list of room-temperature magnetic materials and offers a new, structurally tunable platform for exploring spintronic and magnetic applications of carbon allotropes.

Structural features of the hyper-porous graphene network (HGN). Structural characterization of the (HGN). (a) Optical image of HGN on a 2-inch Si wafer. (b) TEM image showing nanoscale pores. (c) Converted TEM sketch with pores (<2 nm) as hollow islands. (d-f), Plan-view HAADF TEM images: overview with pores (d), zoomed-in cross-linked edges (e), and atomic detail with 0.35 nm interlayer and 0.21 nm zigzag edge spacing (f). (g-i) Side-view TEM images: vertical layers (g), crosslinking features (h), and 0.12 nm armchair spacing (i). Image from: Advanced Materials
 

Claims of intrinsic magnetism in carbon have long been difficult to establish, since even a trace of ordinary magnetic contamination, iron, cobalt, or nickel, can produce a magnetic signal comparable to the faint ferromagnetism reported in some carbon systems, which typically sits near 10⁻³ emu/g or below in bulk graphite. Prior demonstrations of edge-localized magnetism in graphene nanoribbons and multi-spin nanographene molecules showed the underlying physics could work at the nanoscale, but establishing the same effect reliably in bulk carbon had remained an open problem, requiring evidence that carbon itself, not a contaminant, carries the magnetism, and a structural handle whose removal reversibly weakens the effect.

Researchers at Rice University, together with the University of Minnesota and Switzerland's Paul Scherrer Institute, working with contributing researchers from the Gwangju Institute of Science and Technology, Kyung Hee University, and Myongji University in South Korea, the University of Illinois Urbana-Champaign, the University of West Bohemia in the Czech Republic, and beamline scientists at Lawrence Berkeley National Laboratory's Advanced Light Source and Brookhaven National Laboratory's National Synchrotron Light Source II, have found that ultrathin, epitaxially strained films of ruthenium dioxide (RuO₂) display a spin texture consistent with altermagnetism, a form of magnetic order the material's bulk and thick-film forms have consistently failed to show despite RuO₂ standing for years as one of altermagnetism's leading candidate materials. 

 Illustration of strain-induced emergent magnetism in ultrathin RuO₂/TiO₂. Possible theoretic altermagnetic spin density is rendered with orange and blue visual effects in the top RuO₂ layers using AI. Credit: Rice University/Yichen Zhang.

Using spin-resolved angle-resolved photoemission spectroscopy (ARPES) on a 2.7-nanometer-thick, substrate-strained RuO₂ film, the team observed a spin texture combining mirror-odd and mirror-even components that a comprehensive symmetry analysis rules out explaining through nonmagnetic effects, pointing instead to intrinsically broken time-reversal symmetry.

Researchers at the National University of Singapore (NUS), led by Assistant Professor Ahmet Avsar of the university's Centre for Advanced 2D Materials, have combined a record-fidelity graphene spin-transport platform with magnetic-proximity band engineering to move graphene closer to practical spin-logic and spin-memory devices, across two complementary studies. The work targets one of graphene spintronics' core limitations: interfacial disorder at the electrical contacts that inject and detect spin, which has historically scrambled spin information before it can be read out electrically.

The first study rebuilt the graphene spin-device fabrication process around an inert-glovebox van der Waals assembly, laminating and cleaning the stack to produce atomically flat hexagonal boron nitride (h-BN) tunnel barriers rather than the oxide barriers more commonly used in graphene spin valves. That interface quality translated directly into device performance: nonlocal spin signals reached up to 1.6 kΩ at 2.5 K, spin polarization approached 90% (89% in the lead device), spin lifetime measured about 2.04 nanoseconds with a spin diffusion length of about 4.74 μm, and gate-tunable magnetoresistance exceeded 80%. Critically for eventual device use, the effect persisted at room temperature, where the same device retained a nonlocal spin resistance of about 160 Ω and roughly 42% spin polarization.

West Virginia University, in partnership with the University of Delaware, has been awarded a four-year, $4 million grant from the National Science Foundation's Established Program to Stimulate Competitive Research (NSF EPSCoR) to develop magnetic materials that can be switched using electrical pulses alone, without an applied magnetic field. The project, titled "Spin Control via Topology, Symmetry and Dimensionality," is led by WVU physicist Mikel Holcomb, with UD co-principal investigator Ryan Comes and colleagues Joshua Zide and John Xiao; UD's share of the award comes to close to $1.4 million.

Magnetic materials already anchor widely used memory technologies such as hard drives, but changing their magnetic state normally requires generating a magnetic field, a comparatively energy-hungry and hard-to-miniaturize approach. Controlling magnetism directly with electricity instead, by manipulating electron spin, could enable more energy-efficient memory and tighter integration of magnetic storage with conventional electronics, one of the central goals driving spintronics research.

Researchers at Boston College, University of Chemistry and Technology Prague and Japan's National Institute for Materials Science have built a spin transistor that can be switched either electrically or magnetically from within a single two-dimensional device, using the van der Waals magnetic semiconductor chromium sulfur bromide (CrSBr). The device reaches an electrical on/off ratio of a million percent and a magnetic on/off ratio of 3,000 percent, which the team says is well above what prior spin-transistor efforts have achieved.

The work targets the "von Neumann bottleneck": the energy and speed cost of continually shuttling data, including the billions of parameters in large AI models, between separate compute and memory blocks on a chip. A long-standing goal in spintronics is a single "spin transistor" device that combines a magnetic bit with a semiconducting switch, so it can compute and store data at once. Historically, building one has meant physically joining two different materials, a magnet and a semiconductor, together. "By engineering a single van der Waals crystal, CrSBr, that inherently possesses both semiconducting and magnetic properties, we eliminate losses at interfaces entirely," said Zdeněk Sofer, a materials-synthesis specialist at the University of Chemistry and Technology Prague.

A research team led by Masahito Mochizuki and Xichao Zhang at Waseda University, working with collaborators from the Hong Kong University of Science and Technology, Los Alamos National Laboratory, the Chinese University of Hong Kong, Nanjing University, and the University of York, has shown that magnetic skyrmions can diffuse asymmetrically when confined to a structured environment, moving more readily in one direction than the other even though their underlying thermal motion is random. The work proposes topology and geometry as a new lever for controlling diffusion, with potential relevance to unconventional, physics-based computing hardware.

Skyrmions are particle-like, topologically protected spin textures that can be nudged into motion by tiny thermal fluctuations, and prior work has documented behaviors, such as wall-guided "Brownian gyromotion," that ordinary particles don't exhibit. Directional or asymmetric diffusion of particle-like systems has drawn growing interest for unconventional AI hardware, where geometry rather than circuitry could shape how information propagates. Until now, though, how skyrmions diffuse in structured, chamber-like environments, as opposed to open thin films, had been largely unexplored.

Researchers at Osaka University have designed "bifacial" ladder polymers - rigid, double-stranded polymer backbones with two deliberately different molecular faces - that show chirality-induced spin selectivity (CISS) exceeding ±90%, among the highest spin-polarization values reported for an organic chiral material. 

The team's key innovation is a chirality-assisted synthesis: a C₂-chiral bifacial monomer, built with two different substituents in a syn arrangement, is polymerized so the resulting ladder polymer keeps a uniform facial orientation along the entire chain. That regioselective, "one-handed" backbone is what earlier bifacial polymer designs struggled to control. Thin films of the resulting homochiral polymer self-assemble into one-handed supramolecular helices, with circular dichroism signals over 100 times stronger than non-ladder or monomeric references, and the chiral structure survives brief exposure to 300°C.

Researchers at Rice University, with contributing authors from the University of Washington, the University of Houston, Oak Ridge National Laboratory, the National High Magnetic Field Laboratory at Florida State University, and the University of Illinois Urbana-Champaign, have used mechanical strain to control and reverse the anomalous Hall effect (AHE) in hexagonal manganese telluride (α-MnTe), a recently identified altermagnet.

Altermagnets are a newly recognized class of magnetic order in which moments are arranged so that time-reversal symmetry is broken - enabling ferromagnet-like effects such as spin splitting and the anomalous Hall effect - while net magnetization remains vanishingly small. That near-absence of stray magnetic fields makes altermagnets attractive for spintronic devices, but it also makes them difficult to probe: α-MnTe naturally forms three magnetic domains oriented 120 degrees apart, and their signals average out in standard neutron diffraction measurements, obscuring the true direction of the in-plane magnetic moments.

Researchers at the Indian Institute of Technology (IIT) Bhubaneswar, led by Dr. Manish Kumar Mohanta of the Department of Physics, working with collaborators at Virginia Commonwealth University in the US, have theoretically predicted that a monolayer of iron trichloride (FeCl₃), just three atoms thick, can host i-wave altermagnetism, one of the rarer symmetry classes within the recently identified altermagnetic phase.

Altermagnetism has drawn growing interest in condensed matter physics because it combines features of both ferromagnets and antiferromagnets. Like antiferromagnets, altermagnetic materials produce essentially no stray magnetic fields, which means electronic components built from them can be packed closer together without magnetic interference. At the same time, they can generate and control spin-polarized electric currents, the property that makes them relevant to spintronics, where information is encoded in electron spin as well as charge.