Plate Nº 38 · recorded October 10, 2026
PhysicsReported finding
Strain switches on altermagnetism in ultrathin ruthenium dioxide
Physicists report electron spin patterns consistent with altermagnetism in ultrathin ruthenium dioxide films placed under lattice strain. The result could inform future spintronic memory designs.
By Nathan Brooks3 min read573 words
In brief
- Published August 27, 2026 in Science Advances (DOI: 10.1126/sciadv.aec2917)
- Bulk ruthenium dioxide had been considered nonmagnetic after years of debate
- Ultrathin films only a few atomic layers thick showed spin patterns consistent with altermagnetism when held under lattice strain
- Researchers used spin-resolved angle-resolved photoemission spectroscopy to map electron spin directions
- Collaboration involved Rice University, the University of Minnesota, and the Paul Scherrer Institute
Physicists report electron spin patterns consistent with altermagnetism — a magnetic state proposed only recently — in ultrathin ruthenium dioxide films placed under strain. The finding, published August 27, 2026 in Science Advances, came from a collaboration between Rice University, the University of Minnesota, and the Paul Scherrer Institute.
What is altermagnetism?
Altermagnetism is a third class of magnetic behavior, sitting alongside ferromagnetism (think refrigerator magnets) and antiferromagnetism, where neighboring atomic magnets point in opposite directions. In altermagnets, electron spins arrange in patterns that break certain symmetries in the crystal.
That arrangement produces properties useful for spintronics, a field building devices that exploit both the charge and the spin of electrons to store and process information. Researchers first proposed altermagnetism only recently, and interest has grown because it can combine advantages of both ferromagnetism and antiferromagnetism.
What did the team actually see?
Rice physicist Ming Yi, working with Bharat Jalan of the University of Minnesota and Milan Radovic of the Paul Scherrer Institute, examined ruthenium dioxide films only a few atomic layers thick. Physicists spent years debating whether the bulk form of this material was magnetic, and ultimately agreed that it was not.
"Ruthenium dioxide was one of the first materials to be proposed as an altermagnetic candidate, but studies on its bulk form didn't return evidence of magnetism," Yi said. "Our research shows that its ultrathin form, on the other hand, may be the key in making it magnetic."
The team probed the material's spin texture — the spatial arrangement of electron magnetic moments — using spin-resolved angle-resolved photoemission spectroscopy. The technique fires photons at a sample and measures the electrons ejected in response, revealing each electron's spin direction.
Why does strain matter?
The altermagnetic signal appeared only when the crystal sat under lattice strain, a squeezing or distortion of the material's atomic framework. Remove the strain, and the spin pattern looks just like that of ordinary, nonmagnetic ruthenium dioxide.
"The strain-dependent nature suggests that we may be able to use lattice strain as a tuning knob to induce or control altermagnetism," said Yichen Zhang, first author on the paper and a recent Rice graduate. "This could be extremely useful when thinking about next-generation spintronics and RAM architectures."
What's still uncertain?
The team describes its result as evidence consistent with altermagnetism rather than a confirmed detection. Zhang noted that the spin textures fit "unconventional magnetism" under the team's experimental conditions, and that bulk and ultrathin forms may have "distinctly different magnetic properties."
The work also highlights how difficult it can be to pin down quantum materials' behavior.
"This work shows just how complex these questions can be," Yi said.
High-quality material preparation and careful measurement protocols proved critical, he added, allowing the team to determine both the magnetic state symmetries and a potential way to manipulate them in next-generation quantum materials.
What comes next?
If other groups confirm altermagnetism in ultrathin ruthenium dioxide, follow-up work would likely tackle:
- Engineering films with precisely tuned strain levels
- Building prototype spintronic memory devices using the new magnetic state
- Comparing the experimental spin patterns against theoretical altermagnet models
The research received funding from the U.S. Department of Energy (grants DE-SC0026179, DE-SC0020211, DE-SC0024710), the Gordon and Betty Moore Foundation's EPiQS Initiative (GBMF9470), and the Robert A. Welch Foundation (C-2175).
The paper appeared in Science Advances 12(31), DOI: 10.1126/sciadv.aec2917.
via news.rice.edu (Original)
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