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A Magnet That Flips with a Current: A Step Toward Energy-Efficient Chips ✛ ✎

Original: "Demonstration of room-temperature, magnetic-field-free, and ultralow-power spin-orbit torque logic device based on composition-uniform van der Waals magnet Fe3GaTe2"
· Zhengxiao Li, Qianbiao Liu, Wenliang Zhu, Lijun Zhu
arXiv:2609.04600v1 · 2026-09-04 · arXiv non-exclusive · independent analysis · 2 min
Materials
Scientists have built a tiny magnetic switch that works at room temperature and uses very little energy.

A magnetic bit that flips with a gentle nudge of current, not a strong magnet. That's how the new device works: a thin layer of the magnetic material Fe3GaTe2 sits on a platinum film. When a short electrical pulse runs through the platinum, the magnetic layer changes its magnetization direction. It's like a light breeze turning a page, even though normally you'd need a hand.

Earlier, such switches relied on metal alloys that are hard to make thin and hard to integrate with silicon chips. The new material, Fe3GaTe2, belongs to a class called van der Waals magnets. These are layered crystals, similar to graphite in a pencil: you can peel them into very thin sheets. The team took a layer just 37 nanometers thick, thousands of times thinner than a human hair, and coated it with 4 nanometers of platinum. Then they etched a special cross-shaped pattern to bend the electric field.

Why does switching work without an external magnet? When current flows through platinum, electrons with spin up and spin down deflect in opposite directions. This creates a spin current that pushes on the magnetic layer. In a plain straight film, that push is along the surface and can't flip the magnetization, which points perpendicular. But the asymmetric cross shape curves the field, giving the push the right direction. So a small current flips the magnetic bit.

Measurements show the device holds its state reliably at room temperature, and writing one bit takes only 1.5 femtojoules. That's about the energy of a single photon of visible light. For comparison, current devices based on tungsten and cobalt-iron-boron need 40 times more energy. This saving could lead to chips that run cooler and last longer on a battery, which matters for phones, sensors, and artificial intelligence systems.

An energy of 1.5 fJ is comparable to the energy of a single visible-light photon, yet it is enough to switch a magnetic bit.

I_c = I_{c0}\left(1-\frac{1}{\Delta}\ln\frac{\tau}{\tau_0}\right)
Switching current as a function of pulse duration, where Ic0 is the intrinsic critical current, Δ is the thermal stability factor, and τ0 is the attempt time (~1 ns).
P = \frac{(I_c/w_0)^2 L w \tau}{\sigma_{xx} d}
Estimate of write energy for industrial channel dimensions, where Ic is the switching current, w0 and d are the original width and thickness of the device, L and w are the channel length and width, and σxx is the channel conductivity.
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