Electrically tunable spin polarization in graphene opens path toward low-power spintronic devices

Graphene spin filtering via magnetic proximity. Credit: University of Manchester

Researchers at the National Graphene Institute, in collaboration with the National University of Singapore, have shown that the magnetic behavior of electrons in graphene can be precisely controlled using electricity, revealing unusually large spin signals in a carefully engineered graphene system.

The study, published in Nature Communications , demonstrates how placing graphene close to a magnetic material can influence the spin of electrons without permanently altering graphene itself. By combining this magnetic proximity effect with graphene superlattices and operating at very low charge densities, the researchers were able to strongly tune how spins move through the material.

"This work shows that by combining graphene with nearby magnetic materials, we can gain a high level of control over electron spin using electrical signals alone," said Dr. Daniel Burrow, from the University of Manchester. "In simple terms, we are learning how to pass information through graphene using the spin of electrons rather than their electrical charge."

Electron spin is a quantum property that can act like a tiny magnetic compass needle. While conventional electronics rely on the movement of charge, spin-based approaches aim to use this magnetic degree of freedom to process and carry information, potentially reducing energy losses.

How proximity reshapes spin flow

In the study, the team used cobalt contacts to induce magnetism in graphene through proximity, meaning the graphene itself does not become magnetic. They then injected and detected pure spin currents, allowing them to probe how spin transport changes across different electronic regimes.

Near the charge neutrality point , where graphene has very few mobile charge carriers, the researchers observed a clear reversal of the spin signal. This behavior indicates that the magnetic proximity effect creates a spin-dependent energy splitting in graphene, which governs how spins travel through the material.

Importantly, the same effect was also observed at additional neutrality points that appear when graphene is precisely aligned with hexagonal boron nitride. These so-called superlattice features show that proximity-induced spin control applies not only to graphene's original electronic bands but also to those reconstructed by the superlattice structure.

"Our measurements show that the same underlying mechanism controls spin transport across all these regimes," Burrow said. "That tells us we are seeing a robust physical effect rather than something specific to a single device setting."

Largest signals in bilayer superlattices

The strongest signals were observed in a bilayer graphene superlattice device designed to open an energy gap in the electronic structure. In this specific system, the researchers measured spin polarizations approaching 50% and nonlocal spin resistances exceeding 300 ohms. These values are nearly two orders of magnitude larger than those measured away from charge neutrality in the same experimental platform.

The study shows that low carrier density, combined with magnetic proximity effects and engineered band structure, can greatly enhance spin filtering and detection. While the work focuses on demonstrating the physics, the authors note that electrical control of spin at low power could be relevant for future spin-based electronic technologies.

"This research shows that we can engineer graphene systems where spin signals become both large and electrically tunable," said Dr. Jesus Toscano Figueroa, a co-author of the study. "That opens up new ways to explore spin transport in two-dimensional materials and brings us closer to using these effects in practical devices."

Publication details

Yijie Lin et al, Spin magnetic proximity effect in graphene superlattices, Nature Communications (2026). DOI: 10.1038/s41467-026-71915-w

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Electrically tunable spin polarization in graphene opens path toward low-power spintronic devices (2026, June 18)

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