SLAC researchers confirmed the existence of altermagnetism, a third magnetic phase first proposed in 2022. The team showed that manganese telluride exhibits this unique property. By using X-rays in 2024 and 2025, they found a chiral signal. This discovery could help build better memory devices and faster data centre technology.
Physicists have experimentally confirmed the existence of altermagnetism, a third phase of magnetism that combines properties of ferromagnetism and antiferromagnetism. The finding, led by researchers at the US Department of Energy’s SLAC National Accelerator Laboratory, provides evidence for a magnetic phase first proposed in 2022. The study was published in Science.
The team established that manganese telluride (MnTe), previously classified as an antiferromagnet, exhibits altermagnetic properties. The researchers detected chirality, or handedness, in its magnetic structure. This asymmetry distinguishes altermagnets from conventional antiferromagnets, in which opposing electron spins cancel each other out without producing net magnetisation.
To detect this property, the researchers exposed MnTe to circularly polarised X-rays at the European Synchrotron Radiation Facility in France. They compared how the material scattered left- and right-handed X-rays and identified a distinct chiral signal. The experiment was first conducted in 2024 and repeated in early 2025 to confirm the findings.
The discovery could advance spintronics, which uses electron spin alongside electrical charge to process and store information. Unlike ferromagnets, altermagnets have zero net magnetisation, making them stable against external magnetic fields, while retaining the ability to generate spin-polarised currents. Researchers plan to explore controlling these magnetic states using light and electricity for applications in quantum technologies, memory devices and data centres.