First 2D magnet developed at UC Berkeley

Researchers at the Department of Energy's Lawrence Berkeley National Laboratory and the University of California Berkeley announced the development of a two-dimensional cobalt-doped zinc oxide magnet that operates at room temperature and could lead to new applications in computing, electronics, and new tools for the study of quantum physics.

The ultrathin magnet, recently reported in the journal "Nature Communications," could make significant advances in next-generation memory, computing, spintronics, and quantum physics.

"We're the first to make a room-temperature 2D magnet that is chemically stable under ambient conditions," said senior author Jie Yao, an associate professor of materials science and engineering at UC Berkeley.

Magnetic components of today's memory devices are typically made of magnetic thin films. However, these magnetic films are still three-dimensional at the atomic level – hundreds or even thousands of atoms thick. For decades, researchers have searched for ways to make thinner and smaller 2D magnets and thus enable data to be stored at a much higher density.

Previous achievements in the field of 2D magnetic materials have brought promising results. Nonetheless, these early 2D magnets lose their magnetism and become chemically unstable at room temperature.

"State-of-the-art 2D magnets need very low temperatures to function. But for practical reasons, a data center needs to run at room temperature," said Yao. "Theoretically, we know that the smaller the magnet, the larger the disc's potential data density. Our 2D magnet is not only the first that operates at room temperature or higher, but it is also the first magnet to reach the true 2D limit: It's as thin as a single atom!"

The latest single-atom-thick magnet was synthesized from a solution of graphene oxide, zinc, and cobalt – called a cobalt-doped van der Waals zinc-oxide magnet.

Just a few hours of baking in a conventional laboratory oven transformed the mixture into a single atomic layer of zinc-oxide with a smattering of cobalt atoms sandwiched between layers of graphene. In the final steps, the graphene is burned away, leaving behind just the plane of cobalt-doped zinc oxide.

"With our material, there a no major obstacles for industry to adopt our solution-based method," said Yao. "It's potentially scalable for mass production at lower costs."

The researchers say that the new materials – which can be morphed into almost any shape without breaking and is one-millionth the thickness of a single sheet of paper – could help advance the application of spin electronics, or spintronics, a new technology that uses the orientation of an electron's spin rather than its charge to encode data.

"Our 2D magnet may enable the formation of ultra-compact spintronic devices to engineer the spins of the electrons," said Rui Chen, a UC Berkeley graduate student in the Yao Research Group and lead author of the study. "This discovery is exciting because it not only makes 2D magnetism possible at room temperature, but it also uncovers a new mechanism to realize 2D magnetic materials."

The researchers say that their discovery will also enable new opportunities to study quantum physics.

"Our atomically thin magnet offers an optimal platform for probing the quantum world," Yao added. "It opens up every single atom for examination, which may reveal how quantum physics governs each single magnetic atom and the interactions between them. With a conventional bulk magnet where most of the magnetic atoms are deeply buried inside the material, such studies would be quite challenging to do."

With the quickly advancing optimization of data storage methods over the last couple of decades, humanity has quickly reduced space and increased speeds – with terabytes worth of storage in solid-state devices being the same size as flash drives from a decade ago. Now, the capabilities for smaller, faster, and more capacity are probably not far off, with storage capabilities alone potentially multiplying into amounts that the average person could have no hope of ever filling its entirety.