When Yijie Lin and his team adjusted the electric field in a flake of bilayer graphene just right, something remarkable happened: the spin signal flipped, clear and strong, like a compass needle reversing in perfect sync with a switch. At the National Graphene Institute in Manchester, in collaboration with the National University of Singapore, researchers have achieved unprecedented electrical control over electron spin in graphene—a breakthrough that could pave the way for ultra-low-power electronics. Unlike conventional devices that rely on the movement of electric charge, spintronics harness the magnetic orientation of electrons, known as spin, to encode and transmit information. This quantum property, if mastered, could drastically reduce energy waste in computing. The team’s work, published in Nature Communications, demonstrates that by placing graphene near a magnetic material—specifically using cobalt contacts—they can induce powerful spin effects without altering graphene’s intrinsic properties. This magnetic proximity effect, long theorized, is now shown to be electrically tunable, a critical step toward practical applications.
The real surprise came near the charge neutrality point, where graphene hosts almost no free electrons. Here, the researchers observed a dramatic reversal of the spin signal, a telltale sign that the magnetic proximity was creating a spin-dependent energy gap—essentially filtering electrons based on their spin direction. Even more striking, this effect persisted in graphene superlattices, formed by precisely aligning the material with hexagonal boron nitride. These engineered structures reshape graphene’s electronic bands, yet the same spin control emerged, proving the effect’s robustness across different quantum environments. “Our measurements show that the same underlying mechanism controls spin transport across all these regimes,” said Dr. Daniel Burrow of the University of Manchester. “That tells us we are seeing a robust physical effect rather than something specific to a single device setting.”
The strongest results came from a bilayer graphene superlattice designed to open an energy gap—a feature essential for transistor-like operation. In this system, the team measured spin polarizations approaching 50% and nonlocal spin resistances exceeding 300 ohms, nearly 100 times larger than signals observed in the same device under different conditions. These are among the largest spin signals ever recorded in graphene, and their electrical tunability marks a leap forward. “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. As the world seeks more efficient computing solutions, this work offers a glimpse of a future where information flows not through charge, but through the subtle quantum whisper of spin—guided, for the first time, with precision by an electric field.