You have probably never heard of them, but skyrmions have huge potential to offer for an extremely compact and ultrafast way of storing and processing data. However, up until now, scientists have only been able to produce skyrmions at extremely low temperatures that are impractical for useful applications.
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A multilayer system
This may soon change. “We have produced a multilayer system consisting of various sub-nanometer-thick ferromagnetic, noble metal and rare-earth metal layers, in which two different skyrmion states can coexist at room temperature,” said Hans Josef Hug leader of the Empa research group responsible for the discovery.
Using a magnetic force microscope that they developed at Empa, Hug and his team have been studying skyrmions. They developed material layers from iridium (Ir), iron (Fe), cobalt (Co), platinum (Pt), and rare-earth metals terbium (Tb) and gadolinium (Gd) that generate two types of skyrmions in large numbers.
These skyrmions which are only a few nanometers in size can be detected by the magnetic force microscope and can be distinguished due to their different sizes and intensities. “The larger skyrmion, which also creates a stronger magnetic field, penetrates the entire multilayer system, i.e. also the middle ferrimagnetic multilayer. The smaller, weaker skyrmion, on the other hand only exists in the two outer multilayers,” explained the scientists.
A useful innovation
Why is this useful?
Because the two different skyrmions can be used to represent binary data of 0 and 1. This would allow for their use in data processing.
Now, the researchers hope they can use skyrmions in practical applications that are also scalable. “The multilayers we have developed using sputtering technology can in principle also be produced on an industrial scale,” said Empa researcher Andrada-Oana Mandru, the first author of the study.
The scientists also argue that their skyrmions can be used to build three-dimensional data storage devices with even greater storage density. The study was published in the journal Nature Communications.