Experiments Confirm a Third Type of Magnetism Called Altermagnetism

Scientists led by the U.S. Department of Energy’s SLAC National Accelerator Laboratory say they have found experimental proof of a third type of magnetism, according to ScienceDaily. The work was published in the journal Science. The researchers say the phase, called altermagnetism, combines features of the two magnetic types that scientists have long recognised.

The team studied manganese telluride, a material that had been treated for decades as an ordinary antiferromagnet. Their measurements pointed to chirality, a built-in asymmetry in the material’s magnetic structure. Lead author Daniel Jost, an associate scientist at SLAC and the Stanford Institute for Materials and Energy Sciences, said the results provide strong experimental confirmation that the third phase is real.

How the measurements were made

The experiments took place at the European Synchrotron Radiation Facility (ESRF) in France. Its ID32 beamline produces tightly controlled polarised X-rays. The beams were polarised so that their waves twisted in one of two opposite senses, described as left or right, as they travelled.

By comparing how the material scattered these two kinds of light, the team looked for chirality. Jost explained that chiral materials scatter the two beams differently, while non-chiral materials scatter them the same way. The material showed a clear difference, which matched the signal expected from altermagnetism and would not be seen in a conventional antiferromagnet.

The team first ran the experiment in 2024. They returned in early 2025, repeated the measurements and obtained the same results. Rachel Nickel, a postdoctoral scientist at ESRF and a co-author, said the technique helped confirm the material’s altermagnetic behaviour.

Two older categories and the new one

Magnetism is linked to a quantum property of electrons called spin. In ferromagnets, spins point the same way and create a magnetic field that people have used for thousands of years. In antiferromagnets, neighbouring spins point in opposite directions, cancelling each other out. That category was identified in 1933.

Recent experiments showed materials that did not fit either group. They had alternating spins and no overall magnetisation, yet could carry useful spin currents. In 2022, researchers proposed the term altermagnets for this suggested third class. The difference lies in how the atomic structures around opposing spins are rotated relative to one another.

Why it matters for future technology

The findings could benefit spintronics, a field that uses electron spin alongside electrical charge to handle information. Researchers say this could lead to devices that run faster, resist interference better and use much less electricity. Memory systems and large data centres are among the areas mentioned.

Jost said ferromagnets can be disturbed by outside magnetic fields, while antiferromagnets are hard to read. Altermagnets, he said, have no net magnetisation, which makes them stable, yet can still generate the spin-polarised currents needed to extract information. The next step is to learn how to control these states with light and electricity. Part of the costs were covered by the Office of Science at the U.S. Department of Energy.

Frequently asked questions

Sources

• ScienceDaily: SLAC scientists find conclusive proof of a mysterious third type of magnetism

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