Heat-assisted magnetic recording

A next-generation data storage scheme that uses plasmonics to overcome the limitations of current magnetic storage technology is reported online this week in Nature Photonics.

As magnetic grains in a disk get smaller they also become unstable and lose their ability to store information, but raising their temperature can resolve the problem. William Challener and his colleagues built a proof-of-principle heat-assisted magnetic recording (HAMR) system and recorded data at a density of about 48,000 gigabytes per square metre. Although this value is comparable to today's state-of-the-art hard disk drives, it has the potential to be scaled to values that are out of reach of conventional magnetic recording, which is now close to approaching its theoretical limits.

The key to the HAMR prototype is a plasmonic transducer integrated into a recording head that flies just 15 nanometres above a magnetic disk rotating at 2,700 revolutions per minute. The lollipop-shaped transducer focuses light from a semiconductor laser down to a tiny spot, allowing highly localized heating in the magnetic disk and therefore the creation of small, dense data tracks.