Ultra-Thin Magnetic Metal Could Supercharge AI and Spintronic

Scientists at the University of Minnesota have discovered how to turn a normally non-magnetic metal into a magnetic powerhouse by making it incredibly thin—just two atoms thick.

This finding could upend how we build faster computers and smarter electronic devices, particularly for artificial intelligence applications. The research team used an advanced growth technique to create ultra-thin layers of ruthenium dioxide (RuO2) that exhibited surprising magnetic behavior despite being thinner than a billionth of a meter.

Stretching Materials Into New Behaviors

The key to this discovery lies in something called epitaxial strain—imagine stretching or compressing a rubber band to change its properties. By applying this strain to atomically thin RuO2 layers, researchers transformed a typically non-magnetic material into one with powerful magnetic characteristics.

“Our work shows that RuO2 is not just metallic at the atomic scale—it’s the most metallic material we’ve observed in any oxide, rivaling even elemental metals and 2D materials, second only to graphene,” said Bharat Jalan, the senior author and professor in the University of Minnesota’s Department of Chemical Engineering and Materials Science.

What makes this achievement particularly noteworthy is that the material maintained its metallic properties even at such extreme thinness. Most materials become unstable or lose their useful characteristics when reduced to just a few atoms thick.

The Anomalous Hall Effect Breakthrough

The researchers observed what’s called the anomalous Hall effect—a phenomenon where electrical current bends in the presence of a magnetic field. This effect is crucial for next-generation memory and data storage devices, but it typically requires enormous magnetic fields to achieve in metallic RuO2.

Here’s where the breakthrough becomes significant: the team achieved this effect using much weaker magnetic fields (less than 9 Tesla) compared to the extreme conditions (around 50 Tesla) previously required. That’s like getting the same result with a refrigerator magnet instead of needing a massive industrial electromagnet.

Key Findings Include:

• Magnetic effects observed in films just 2 unit cells thick (less than a billionth of a meter)
• Anomalous Hall effect achieved with magnetic fields under 9 Tesla vs. previous requirement of ~50 Tesla
• Material remained highly metallic and structurally stable despite extreme thinness
• First experimental demonstration of altermagnetic state in ultra-thin RuO2

Resolving Scientific Debates

This work addresses ongoing scientific controversies about RuO2’s magnetic properties. The abstract notes that the research “resolves recent debates” by pinpointing epitaxial strain as the definitive origin of magnetism in these thin films. Previous studies had conflicting results about whether RuO2 could exhibit magnetic behavior under normal conditions.

The team’s density functional theory calculations revealed that epitaxial strain stabilizes what researchers call a “noncompensated magnetic ground state”—essentially creating a magnetic imbalance that wouldn’t exist in the unstrained material.

Beyond Laboratory Curiosity

“It’s exciting because this isn’t just a laboratory curiosity—we’re looking at a material that can be integrated into real devices,” explained Seunnggyo Jeong, a postdoctoral researcher and first author on the paper. “This could have major implications for developing smaller, faster, and more energy-efficient technologies, directly relevant to artificial intelligence.”

But why does this matter for everyday technology? Current electronic devices waste enormous amounts of energy as heat. Spintronic devices—which use electron spin rather than just electrical charge—could dramatically reduce this energy loss while increasing processing speed.

Engineering Materials Atom by Atom

“This discovery shows how we can unlock completely new behaviors in materials just by controlling them at the atomic scale,” said Tony Low, a professor in the Department of Electrical and Computer Engineering and co-author. “Our calculations confirmed that strain changes the internal structure of RuO2 in just the right way to make this altermagnetic behavior possible.”

The altermagnetic state represents a newly recognized class of magnetic materials that combines properties of both ferromagnets and antiferromagnets. This gives researchers more flexibility in designing materials with specific magnetic behaviors.

Future Applications and Next Steps

What’s particularly promising is the material’s compatibility with existing manufacturing processes. The researchers used hybrid molecular beam epitaxy—a sophisticated but established technique—to create these ultra-thin films with precise control over thickness and strain.

The team plans to explore how different combinations of strain and layering can engineer even more exotic material properties. Their ultimate goal involves developing platform materials for quantum computing, spintronics, and low-power electronics that could power the next generation of AI systems.

This research demonstrates how understanding materials at the atomic level can unlock entirely new technological possibilities—turning the seemingly impossible task of creating magnetic behavior in non-magnetic materials into reality through careful engineering.