According to Phys.org, researchers from Japan’s Institute of Science Tokyo have developed a theoretical framework that uses light to create non-reciprocal magnetic interactions in solids. The team led by Associate Professor Ryo Hanai demonstrated that irradiating magnetic metals with carefully tuned light frequencies induces torques that drive magnetic layers into spontaneous, persistent rotation. Their findings, published in Nature Communications on September 18, 2025, show that the well-known RKKY interaction in magnetic metals can become non-reciprocal under light irradiation. The required light intensity for these effects falls within current experimental capabilities. This work effectively creates situations where Newton’s third law – action and reaction – gets violated in solid-state systems.
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What this actually means
Here’s the thing – we’re not talking about breaking fundamental physics. We’re talking about creating systems where the usual rules don’t apply because they’re being constantly pumped with energy. Think of it like those predator-prey relationships in nature where the interaction isn’t symmetrical. The predator chases, the prey runs – but there’s no equal and opposite reaction in the traditional sense.
Basically, the researchers found a way to use light to create that same kind of asymmetric interaction between magnetic layers. One layer tries to align with the other, while the other tries to anti-align. The result? They start chasing each other in a continuous rotation that just keeps going as long as the light’s on. It’s like creating a microscopic magnetic merry-go-round that runs on light instead of electricity.
Why this matters beyond the lab
Now, you might be thinking this sounds like pure academic curiosity. But the implications are actually pretty significant. We’re looking at potential applications in spintronic devices and frequency-tunable oscillators that could be controlled with light instead of electrical currents.
And here’s where it gets really interesting – this bridges two fields that don’t usually talk to each other. Active matter physics (think biological systems, swarms, that kind of thing) and condensed matter physics (your traditional solid-state materials). When you can apply concepts from living systems to electronic materials, you open up entirely new ways to think about device design.
The bigger picture
So what’s the real significance here? We’re seeing the beginning of what you might call “programmable materials” – systems where you can dial in specific behaviors using external controls like light. The fact that they can do this with magnetic interactions specifically is huge because magnetism is already fundamental to so much of our technology.
I think we’re going to see more of this kind of research where scientists take inspiration from biological systems and apply it to engineered materials. After all, nature has had billions of years to figure out efficient, complex behaviors. Why not borrow some of those tricks for our own technology?
The team mentions this could extend to Mott insulators, superconductivity, and other quantum materials. That’s not just incremental improvement – that’s potentially opening up entirely new approaches to controlling quantum states. And that’s something worth chasing.
