Scientists Harness One of Nature’s Strange Quantum Properties—Spin—for Faster Electronics
A new class of materials—polymers with perfectly arranged molecular structures—can transport spin signals more effectively and over longer distances.
May 28, 2025 I By Dave DeFusco
Imagine electronics that run faster, cooler and more efficiently—not by using electricity alone but by harnessing one of nature’s strange quantum properties: spin. That’s the promise of spintronics, an emerging technology that goes beyond traditional electronics by using the “spin” of electrons—essentially, the tiny magnetic direction each electron carries—to store and transmit information.
Scientists from UNC-Chapel Hill and Purdue University have developed a new class of materials—polymers with perfectly arranged molecular structures—that can transport spin signals more effectively and over longer distances than ever before. This discovery, described in the paper “Stereoregular Radical Polymers Enable Selective Spin Transfer” and published in Science Advances, may lay the groundwork for faster, smaller and more energy-efficient technologies ranging from memory storage to quantum computing.
At its heart, spintronics is about using the spin of electrons, not just their charge, to process information. In traditional electronics, the movement of electrons—electrical current—is used to turn transistors on or off. But spintronics could allow devices to operate without moving charges at all, instead transmitting information using spin “currents.”
“This could mean less heat, lower power consumption and more efficient devices; however, using spin instead of charge isn’t easy,” said Frank Leibfarth, a senior author of the study and Royce Murray Distinguished Term Professor of Chemistry at UNC. “It requires materials that can maintain the orientation of an electron’s spin without it quickly scattering or fading out, and transmit it reliably over long distances.”
Most current materials used for this, like certain metals, have serious limitations: they don’t hold spin for long, and they often require doping or the use of heavy atoms to work at all. The research team tackled this problem by designing an entirely new kind of material: a special polymer that can carry spin currents over long distances without the need for chemical doping or unstable components.
Their secret is a highly controlled way of building polymers—long chains of repeating molecules—that are not only stable and flexible but also have magnetic properties embedded in every unit. These are known as radical polymers, and they include a special kind of unpaired electron, called a radical, that makes them naturally magnetic.
“What’s promising is how we arranged these radicals,” said Leibfarth. “Using a method called stereoselective cationic polymerization, we carefully controlled the 3D arrangement, or stereochemistry, of every link in the chain. Think of it like lining up a row of compass needles so they all point in the same direction, instead of randomly.”
This perfect alignment dramatically improved how spins travel along the polymer chain. It’s the molecular equivalent of paving a smooth highway for spin signals, instead of forcing them to bounce around rough terrain. In simpler terms, stereochemistry is about whether a molecule is built in a tidy, repeating pattern or a chaotic jumble. The team created different versions of their radical polymer—one neat and orderly, called isotactic, and others more mixed up, called atactic.
They ran simulations and experiments to see how well these different polymers aligned their radicals and conducted spin. The orderly version came out on top, showing more consistent radical alignment, longer distances over which spin could travel and higher electrical conductivity.
“These results suggest that controlling a polymer’s stereochemistry is key to building better spintronic materials, a concept that had not been fully explored until now,” said Leibfarth. “To prove their polymer could actually conduct spin, we built a test device with layers of materials stacked together. We used a nickel-iron alloy to generate a spin current, our new polymer as the transport layer, and a thin film of palladium to detect it.”
They then used a method called ferromagnetic resonance spectroscopy to watch how spin waves moved through the polymer. The results were striking: Not only did the polymer successfully carry the spin signal, it also showed long diffusion lengths, meaning the spins stayed intact over longer distances than in most other organic materials.
Even more telling, the researchers could reverse the signal simply by flipping the magnetic field—strong evidence that the polymer was indeed carrying pure spin current.
“This study opens a new frontier in organic materials for spintronics,” said Leibfarth. “Unlike many other options, these polymers don’t need doping, heavy metals or high-temperature treatment to work. They’re stable, flexible and—thanks to their clever molecular design—able to do things we’ve only seen in more complex or less practical systems.”
With continued development, these materials could lead to: Faster and more efficient memory storage in computers and phones; quantum devices that use spin for ultra-secure communication; and flexible electronics that bend and stretch like plastic but compute like silicon. And because they’re organic and easy to process, they could even reduce the cost and environmental impact of future electronics.
“By mastering how to control the shape and structure of a new type of magnetic polymer, we’ve taken a step toward practical, powerful spintronic devices,” he said.