Altermagnetism: The New Kind of Magnetism That Could Power Future Computers

For about a century, textbooks have sorted magnetic materials into a few families, with ferromagnets like iron as the familiar example. In the last few years physicists have recognised a genuinely new family: altermagnets. On 5 October 2026 a team at the University of Central Florida reported evidence of altermagnetism in a thin, layered and highly tunable material^[1]. It could matter for the computers of the future. Here is what it means.

Where magnetism comes from

Every electron has a property called spin, which makes it behave like a tiny bar magnet pointing “up” or “down”. In most materials these tiny magnets point in random directions or cancel in pairs, so there is no overall effect. In magnetic materials, the atoms' magnetic moments line up in a regular pattern called magnetic order. The pattern decides how the material behaves.

Why the “best of both” matters

Spintronic devices need currents in which most electrons share the same spin (spin-polarised currents). Ferromagnets provide these, but their stray magnetic fields interfere with neighbouring components, which limits how tightly devices can be packed. Antiferromagnets have no stray fields, but their electrons are not spin-split, so they are hard to read and write electronically. Altermagnets combine the advantages: they can generate and detect spin currents without producing stray fields^[1]. Their magnetic patterns can also switch very quickly, which is why researchers mention ultrafast memory and terahertz devices^[1].

What the UCF team found

The material was Co₁/₄TaSe₂: layers of tantalum diselenide, a transition-metal dichalcogenide, with cobalt atoms slotted (intercalated) between them^[1]. The team, led by Madhab Neupane with graduate student Milo Sprague, used angle-resolved photoemission spectroscopy (ARPES). ARPES shines high-energy light on a sample and measures the energy and direction of the electrons knocked out, which maps the electrons' allowed energies inside the material (its band structure). The team saw distinctive band splitting, and spin-resolved ARPES confirmed that the separated bands carried opposite spins, the signature expected for an altermagnet^[1]. The work was published in Nature Communications^[1].

Because the material is layered, it can be modified, for example by changing what sits between the layers, and the team can watch how electronic and magnetic properties respond^[1]. That tunability is what makes it promising for thin-film devices.

ARPES relies on the photoelectric effect, which you meet at A-Level: a photon of energy hf frees an electron if it exceeds the work function φ, and the electron leaves with kinetic energy E_k(max) = hf − φ. ARPES adds the electron's direction, which reveals its momentum inside the material.

Magnetism, electron spin and the photoelectric effect are all exam topics that suddenly look modern once you see them in research. For the physics of fields in a familiar device, read how wireless charging works.