Skyrmion breakthrough could boost hard drive capacities

Scientists at the University of Hamburg have successfully written and erased individual skyrmions for the first time, paving the way to an explosion in magnetic storage capacity.

First postulated as a theoretical particle by physicist Tony Skyrme in 1962, skyrmions have resisted giving up their secrets for many decades. Described as a magnetic vortex, a skyrmion is a two-dimensional knot-like structure which is considerably more stable than other magnetic structures - including those used in modern magnetic storage devices like hard drives. As a result, they can be shrink down to considerably smaller sizes before becoming unstable and losing their stored data.

Before they can replace traditional magnetic storage methods, however, they need to be readable and writeable. Over the last year, scientists have been successfully reading the topological charge of a skyrmion - but only now have they been successful in writing to them, creating and destroying skyrmions in order to store binary data.

'We finally found a magnetic system in which we can locally switch between ordinary ferromagnetic order and a complex spin configuration,' explains Kirsten von Bergmann, senior scientist of the research group behind the discovery. In their testing, the scientists were able to address, read and erase four skyrmions for the first time - and while a four-bit storage system isn't much use, it's the first step on the path to breaking the superparamagnetic limit of magnetic storage.

Creating more stable magnetic structures will be a requirement if storage capacities are to increase: currently, magnetic storage systems are rapidly approaching the limit of density, meaning we'll have to make hard drives physically larger if we want more storage. Using skyrmions, it's theoretically possible to break through the current limitations of magnetic storage and create devices with a density many times higher than is currently possible.

While that's certainly an end-goal for the technology, the team warns it's far from guaranteed. 'Whether skyrmions will be used as data storage units in our computers, tablets, or smartphones, is not foreseeable,' the University of Hamburg has pointed out in a statement to press on the discovery. 'The experimentally accomplished writing and deleting of skyrmions, however, has demonstrated the feasibility of this technology and paved the way towards a realisation of such devices.'

The team's work is published in the Volume 341 of the Science journal.