Turning up the heat

A discovery by researchers in

could be the key to new high-capacity data storage devices. Based around a microscopic heat source that can raise the temperature of a surface precisely without touching it, the technology could be used in terabyte storage devices.

The current generation of magnetic data-storage devices such as hard drives is approaching a crisis. To increase the capacity engineers are making the storage bits much smaller, cramming more into the same space.

But because of the magnetic properties of the storage material there is a limit to how small they can be. Below a level known as the superparamagnetic limit, the bits become magnetically unstable and, therefore, useless for data storage.

Engineers are working on a new technology known as heat-assisted data storage. This heats the storage medium, which stabilises the recording process; it becomes easier to write the data when the medium is hot and the data is retained when the medium is cooled. To develop this, researchers are looking for new, reliable ways to heat very small areas of material.