Magnetic “hedgehogs” could store big data in a small space

Atomic-scale magnetic models resembling the tips of a hedgehog could result in hard drives with massively larger capacities than today’s devices, suggests a new study. This discovery could help data centers meet the exponentially growing demand for video and cloud data storage.

In a study published today in the journal Science, researchers at Ohio State University used a magnetic microscope to visualize the patterns, formed in thin films of an unusual magnetic material, manganese germanide. Unlike familiar magnets such as iron, the magnetism of this material follows helices, similar to the structure of DNA. This leads to a new zoo of magnetic patterns with names like hedgehogs, anti-hedgehogs, skyrmions, and merons that can be much smaller than today’s magnetic bits.

“These new magnetic models could be used for next-generation data storage, ”said Jay Gupta, lead author of the study and professor of physics in the state of Ohio. “The storage density on hard drives is approaching its limits, due to the small size of the magnetic bits that allow this storage. And that motivated us to research new materials, where we might be able to make the magnetic bits much smaller.

To visualize the magnetic patterns, Gupta and his team used a scanning tunneling microscope in his lab, modified with special tips. This microscope provides images of the magnetic patterns with atomic resolution. Their images revealed that in parts of the sample, the magnetism on the surface was twisted into a pattern resembling the spikes of a hedgehog. However, in this case, the hedgehog’s “body” is only 10 nanometers wide, which is much smaller than current magnetic bits (around 50 nanometers) and almost impossible to visualize. In comparison, a single human hair is about 80,000 nanometers thick.

The research team also found that the hedgehog’s patterns could be moved across the surface with electric currents or reversed with magnetic fields. This foreshadows reading and writing magnetic data, potentially using much less power than is currently possible.

“There is huge potential for these magnetic models to allow data storage to be more energy efficient,” Gupta said, while warning that there is more research to be done before the material can be used. on a data storage site. “We still have a huge amount of basic science to do to understand these magnetic patterns and improve the way we control them. But it’s a very exciting step.

This research was funded by the Defense Advanced Research Projects Agency, a research division of the US Department of Defense. Other Ohio state researchers who co-authored this study include Jacob Repicky, Po-Kuwan Wu, Tao Liu, Joseph Corbett, Tiancong Zhu, Shuyu Cheng, Adam Ahmed, Mohit Randeria, and Roland Kawakami.