SLAC team confirms third magnetic phase in manganese telluride
Researchers at SLAC National Accelerator Laboratory have delivered conclusive experimental proof of altermagnetism, a newly confirmed magnetic phase with potential applications in quantum technologies.
For decades, physics textbooks have recognized two fundamental types of magnetism: ferromagnetism, where atomic spins align in parallel to create the familiar refrigerator magnet, and antiferromagnetism, where neighboring spins point in opposite directions, canceling out any external field. A SLAC-led team has now delivered conclusive experimental proof of a third phase called altermagnetism, confirming that manganese telluride (MnTe) exhibits properties that place it in a category of its own.
The researchers detected altermagnetic properties in MnTe using specialized X-rays at the European Synchrotron Radiation Facility, measuring a phenomenon called chirality — a handedness in how the material’s electrons spin and move. This experimental confirmation matters because altermagnetism combines characteristics of both established types: like antiferromagnets, it produces no net external magnetic field, making it immune to the stray-field interference that plagues ferromagnetic data storage. Like ferromagnets, however, it can carry spin-polarized currents, the foundation of spintronic devices that could one day replace conventional electronics.
The study, published in Science, resolves a question that has hovered over the field since theorists first predicted altermagnets roughly two decades ago. Previous experiments had found suggestive signatures, but none had isolated the definitive chirality signal that would distinguish altermagnetism from more mundane explanations. The SLAC team’s measurement of this specific property in MnTe closes that gap.
What makes the finding practically relevant is the material’s stability. MnTe is a well-studied compound, not some exotic laboratory creation requiring cryogenic temperatures or extreme pressures to maintain its properties. That stability, combined with the absence of stray magnetic fields, positions altermagnets as candidates for next-generation memory and logic devices where neighboring components cannot tolerate mutual interference. The spin-polarized currents they carry are also of interest for quantum technologies, where controlling individual spin states is fundamental to certain computing architectures.
The confirmation arrives at a moment when the semiconductor industry is actively searching for alternatives to charge-based electronics, which face fundamental energy-efficiency limits as components shrink. Spin-based devices promise lower power consumption and faster switching, but ferromagnetic materials have proven difficult to integrate densely because their external fields corrupt neighboring bits. Antiferromagnets solve the interference problem but lack the spin polarization needed for practical devices. Altermagnetism appears to offer both advantages without the corresponding drawbacks — a rare combination in materials physics.
Whether MnTe specifically becomes the platform for commercial devices remains to be seen. The SLAC team’s work establishes the experimental framework for identifying other altermagnetic candidates, and the materials science community now has a clear signature to hunt for. For a field that has worked with essentially two magnetic categories since the nineteenth century, the confirmation of a third is less a disruption than a long-awaited expansion of the toolkit.