‘100 times better’ – Tiny magnetic vortices can transform high-performance computers

Magnetic fields created by Skyrmions

Magnetic fields generated by the sky in a two-dimensional sheet of material made up of iron, germanium, and tellurium. Credit: Argonne National Laboratory

Tiny magnetic vortices could revolutionize high-performance computer memory storage.

Magnets create invisible fields that attract certain substances. A familiar example is fridge magnets. However, they also play a vital role in storing data in computers. By exploiting the direction of the magnetic field (say, up or down), microscopic bar magnets can store a single bit of memory as a zero or a one, which is the basis for computer language.

Scientists at the US Department of Energy’s Argonne National Laboratory are working to replace these bar magnets with tiny magnetic vortices, known as Skyrmions. These vortices, which are as small as a billionth of a meter, form in certain magnetic materials and have the potential to trigger a new generation of memory-storing microelectronics in high-performance computers.

“Stripe magnets in computer memory are like shoelaces tied into a single knot; it takes almost no energy to undo them,” said Arthur McCrae, a Northwestern graduate student working in the Department of Materials Science (MSD) at Argonne, and any malfunction of the magnets. The bar because of some disturbances will affect others.

“In contrast, the sky is like shoelaces tied in a double knot. No matter how hard the strand is pulled, the shoelaces remain tied.” Skyrmions are thus very stable to any perturbation. Another important feature is that scientists can control their behavior by changing the temperature or applying an electric current.

Change Skyrmion groups

Skyrmion clusters change from high-order to unordered with a temperature of -92 F (204 K) to -272 F (104 K). Bright dots indicate arrangement. Credit: Argonne National Laboratory

Scientists have a lot to learn about the behavior of the sky under different conditions. To study them, the Argonne-led team developed artificial intelligence (AI) software working with a high-power electron microscope at the Center for Nanomaterials (CNM), a facility used for DOE’s Office of Science in Argonne. A microscope can visualize the sky in samples at extremely low temperatures.

The team’s magnetic material is a mixture of iron, germanium, and tellurium. In structure, this substance resembles a stack of paper with many leaves. A stack of these sheets contains several skyscrapers, and one sheet of paper can be peeled off the top and analyzed in facilities such as CNM.

“CNM electron microscopy combined with a form of artificial intelligence called machine learning has enabled us to visualize Skyrmion sheets and their behavior at different temperatures,” said Yue Li, a postdoctoral appointee at MSD.

“Our most interesting discovery was that the sky is arranged in a higher-order pattern at -60 degrees below zero[{” attribute=””>Fahrenheit and above,” said Charudatta Phatak, a materials scientist and group leader in MSD. ​“But as we cool the sample the skyrmion arrangement changes.” Like bubbles in beer foam, some skyrmions became larger, some smaller, some merge, and some vanish.

At minus 270, the layer reached a state of nearly complete disorder, but the order came back when the temperature returned to minus 60. This order-disorder transition with temperature change could be exploited in future microelectronics for memory storage.

“We estimate the skyrmion energy efficiency could be 100 to 1000 times better than current memory in the high-performance computers used in research,” McCray said.

Energy efficiency is essential to the next generation of microelectronics. Today’s microelectronics already account for a notable fraction of the world’s energy use and could consume nearly 25% within the decade. More energy-efficient electronics must be found.

“We have a way to go before skyrmions find their way into any future computer memory with low power,” Phatak said. ​“Nonetheless, this kind of radical new way of thinking about microelectronics is key to next-generation devices.”

Reference: “Thermal Hysteresis and Ordering Behavior of Magnetic Skyrmion Lattices” by Arthur R. C. McCray, Yue Li, Rabindra Basnet, Krishna Pandey, Jin Hu, Daniel P. Phelan, Xuedan Ma, Amanda K. Petford-Long and Charudatta Phatak, 21 September 2022, Nano Letters.
DOI: 10.1021/acs.nanolett.2c02275

The study was funded by the DOE Office of Basic Energy Sciences. The team’s machine learning program was run on supercomputing resources at the Argonne Leadership Computing Facility, a DOE Office of Science user facility.

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