For all this time, we’ve known of only two types of magnets: ferromagnets, which stick to your fridge, and antiferromagnets, which don’t. But now, scientists have discovered a third kind of magnetism — one that could rewrite the rules of electronics, data storage, and even superconductors.
Meet altermagnetism, a new class of magnetic materials that combines the best of both worlds. For decades, researchers believed ferromagnetism and antiferromagnetism were opposites, forever incompatible. But altermagnets, first proposed just two years ago, are a sort of bridge between the two.
In a new study published in Nature, scientists have not only confirmed the existence of altermagnetism but also captured the first detailed images of these materials in action.
“We have previously had two well-established types of magnetism,” Oliver Amin, a postdoctoral researcher at the University of Nottingham and co-author of the study, told Live Science. “Ferromagnetism, where the magnetic moments all point in the same direction, and antiferromagnetism, where they point in opposite directions. Altermagnetism is something entirely new.”
Essentially, altermagnets combine the speed and resilience of antiferromagnets with the ease of manipulation found in ferromagnets. These properties mean altermagnets could significantly improve our electronics, with the potential to increase the speed of magnetic memory devices up to a thousand times.
What Makes Altermagnets Special?
Altermagnets are like antiferromagnets with a twist — literally. In these materials, the magnetic moments of neighboring atoms point in opposite directions, much like the black and white tiles on a chessboard. But in altermagnets each magnetic atom is slightly rotated relative to its neighbor. This subtle shift gives altermagnets unique properties, blending the stability of antiferromagnets with the usability of ferromagnets.
“The benefit of ferromagnets is that we have an easy way of reading and writing memory using these up or down domains,” explained Alfred Dal Din, a doctoral student at the University of Nottingham and co-author of the study. “But because these materials have a net magnetism, that information is also easy to lose. Altermagnets, on the other hand, are much more secure and faster.”
To visualize this new form of magnetism, the team used a technique called photoemission electron microscopy (PEEM). By shining polarized X-rays onto a crystal of manganese telluride (MnTe), they mapped the material’s magnetic structure with nanoscale precision. The resulting images revealed an intricate grid of magnetic domains, each with its own distinct spin direction.
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“Different aspects of the magnetism become illuminated depending on the polarization of the X-rays we choose,” Amin added in an interview with Live Science.
| Property | Ferromagnets | Antiferromagnets | Altermagnets |
|---|---|---|---|
| Magnetic Alignment | All magnetic moments align in the same direction. | Magnetic moments alternate in opposite directions (e.g., chessboard). | Magnetic moments alternate but with a twist—each unit is rotated relative to its neighbor. |
| Net Magnetism | Yes (strong external magnetic field). | No (net magnetism cancels out). | No net magnetism, but exhibits ferromagnetic-like properties due to spin symmetry breaking. |
| Time-Reversal Symmetry | Broken (ferromagnets break time-reversal symmetry). | Preserved (antiferromagnets do not break time-reversal symmetry). | Broken (altermagnets break time-reversal symmetry like ferromagnets). |
| Spin Symmetry | Uniform spin alignment (all spins point in the same direction). | Alternating spin alignment (spins cancel out). | d-wave spin polarization (spins alternate with a rotational twist). |
| Material Examples | Iron (Fe), Cobalt (Co), Nickel (Ni). | Manganese oxide (MnO), Chromium (Cr). | Manganese telluride (MnTe), Ruthenium dioxide (RuO₂). |
| Crystal Symmetry | No specific symmetry requirement for ferromagnetism. | Typically requires translational or inversion symmetry. | Requires non-symmorphic symmetry (combines spin-space rotation with real-space screw-axis rotation). |
| Magnetic Domains | Large domains with uniform magnetization. | Small domains with alternating spins. | Complex domains with vortices, antivortices, and domain walls. |
| Applications | Used in refrigerator magnets, hard drives, and electric motors. | Used in spintronics and secure data storage. | Potential for high-speed memory devices, superconductors, and quantum computing. |
| Energy Efficiency | Less efficient due to energy losses in magnetic domains. | More energy-efficient but harder to manipulate. | Highly energy-efficient; combines stability with usability. |
| Environmental Impact | Relies on rare earth elements (e.g., neodymium), which are environmentally damaging. | Less reliant on rare materials but harder to use in practical applications. | Does not require rare earth elements; more sustainable. |
| Key Feature | Strong net magnetization; easy to read/write data. | No net magnetization; highly stable and resistant to external fields. | Combines time-reversal symmetry breaking with zero net magnetization. |
A Potential Leap for Electronics
The implications of this discovery are vast. Altermagnets could improve spintronics, a field that harnesses the spin of electrons to store and process information. Traditional ferromagnets, while effective, have limitations. They can introduce “crosstalk,” which is a blurring between bits of data, and rely on rare and toxic materials. Altermagnets, with their unique spin patterns, promise faster, more efficient, and more sustainable alternatives.
“Altermagnetism will also help with the development of superconductivity,” Dal Din said. “For a long time, there’s been a hole in the symmetries between these two areas, and this class of magnetic material turns out to be the missing link.”
The team also demonstrated how to manipulate altermagnetic materials, creating exotic vortex textures in microscopic devices. These vortices, which resemble tiny magnetic whirlpools, could serve as carriers of information in next-generation memory devices.
Closer to home, magnets play a crucial role in memory devices and common electronics, enabling the storage and retrieval of data in ways that are both efficient and reliable. In hard disk drives (HDDs), for example, data is stored magnetically on spinning platters coated with a ferromagnetic material. Magnetic random-access memory (MRAM), a newer technology, uses magnetic states to store information, offering faster read/write speeds and greater durability compared to traditional RAM.
Beyond speed and efficiency, altermagnets could also reduce the environmental impact of electronics. Magnetic materials are a cornerstone of modern technology, used in everything from hard drives to smartphones. But their production relies heavily on rare earth elements, which are often mined under environmentally damaging conditions. Altermagnets — in this study made from manganese telluride — could lessen our dependence on these resources.
Swapping out traditional components for altermagnetic materials could unlock dramatic gains in speed and efficiency, all while slashing our reliance on rare and environmentally harmful elements.
The Road Ahead
While the discovery of altermagnetism is a major milestone, the journey is far from over. Researchers are now exploring how to scale up these materials for practical applications.
“Our experimental work has provided a bridge between theoretical concepts and real-life realization,” Amin said in a press release. “Hopefully, this illuminates a path to developing altermagnetic materials for practical applications.”
For now, altermagnetism remains confined to the lab. But as scientists continue to unravel its mysteries, this new form of magnetism could soon power the devices of tomorrow — faster, greener, and more resilient than ever before.
The findings appeared in the journal Nature.
