How strange new ‘altermagnets’ could rewrite physics

April 14, 2026

15 min read

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How strange new ‘altermagnets’ could rewrite physics

How the discovery of altermagnets could change physics and computing

By Bob Henderson edited by Clara Moskowitz

Scientists have recently discovered materials with new magnetic prop­erties. In a laboratory at the Massachusetts Institute of Technology, scientists manipulate quartz tubes containing crystals that produce p-wave magnetism.

Tony Luong

On a breezy afternoon last autumn in Cambridge, Mass., in a laboratory thrumming with the huff-whish-huff sound of refrigeration pumps, Massachusetts Institute of Technology graduate student Jiaruo Li was crafting a new device for storing digital data. She was aiming to use an exotic kind of magnetism discovered in the same lab the previous year to make the device faster and more energy-efficient than any competing technology. Her goal was timely given the current AI-driven boom in data centers and the exploding demand for power it portends.

At that moment Li was focused on finding her version of a needle in a haystack: a barely visible flake of nickel bromide with just the right attributes. To get to this point, she’d grown a dime-sized crystal of the compound by baking a glass tube containing nickel bromide powder for 10 days at high temperatures in a computer-controlled oven in an M.I.T. lab. Then, seeking an atomically thin sample, she’d applied a special tape to her creation, peeled it off and transferred the flakes on the tape to a shiny silicon wafer. Now, holding the wafer up to the light, she eyed a galaxy of thousands of tiny golden crystals against a purple mirrored background. “From all these,” she said, “only one or two of them is going to be thin enough.”

Nickel bromide is a sibling compound to nickel iodide, which made news in the spring of 2025 for displaying so-called p-wave magnetism, a phenomenon that had been predicted by theorists in early 2024. P-wave magnets exhibit behaviors that traditional magnets lack, including imparting special properties to electric currents passed through them. The breakthrough was just the latest in a series of revelations over the previous few years related to the discovery of a new class of magnets called altermagnets. These materials surprised many scientists by displaying a combination of attributes that could not only revolutionize computer hardware but rewrite our understanding of the physics of magnets. Equally remarkable: the new magnets weren’t actually new at all. Many were well-known, widely studied compounds with heretofore unrealized superpowers, and their abilities can be explained by simple geometry.

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The magnets of our everyday experience, the ones with north and south poles that keep children’s artwork stuck to refrigerator doors, are called ferromagnets and have been used extensively since prehistoric times. Still, it wasn’t possible to understand them until modern quantum theory was developed in the 1920s. In fact, says University of Oxford physicist Stephen Blundell, “the birth of quantum mechanics could have come from the observation of magnetism.” Physicists Niels Bohr and Hendrika Johanna van Leeuwen proved, independently and before modern quantum theory was devised, that magnetism is incompatible with classical—aka nonquantum—physics.

Magnetism originates in the quantum-mechanical property of electrons called spin. Spin makes an electron behave like a little rotating ball of charge, which furnishes it with a magnetic field similar to that of a tiny bar magnet. (That electrons are, as far as anyone knows, infinitesimally small and therefore not balls at all underlines how spin is an essentially quantum property.) When the spins of a large number of electrons in a crystalline solid align en masse so that their many minuscule magnetic fields combine to produce macroscopic effects, voilà, a ferromagnet is born. A ferromagnet’s most salient feature is its magnetization, or macroscopic magnetic field, consisting of lines of force that can become visible in the self-arrangement of iron filings sprinkled around the magnet.

> The essence of magnetism is the organization of electron spins in a material, and ferromagnetism isn’t the only possibility.

Ferromagnets are immensely important in technology; Blundell calls them “the engine of the modern world.” Power plants, for instance, whirl magnets around to convert mechanical energy into electrical energy. And although most personal computers now rely on solid-state, nonmagnetic memory, the vast majority of the information stored in the worl