Magic roundabouts spin next-gen drives

Scientists at the University of Bonn have identified right-handed and left-handed 'magnetic vortices' that could lead to advances in hard drive efficiency.

The researchers explained that a magnetic vortex is like a traffic roundabout with magnetised atoms circulating.

They form a pattern rather like a ring of tiny bar magnets, so nothing actually moves around the atomic roundabout, but the direction can change.

When the 'north poles' are all pointing clockwise the magnetic vortex is 'right-handed', otherwise the vortex is 'left-handed'.

"The existence of a circular atomic traffic system of this sort has been presumed for several years," said Bonn physics professor Dr Manfred Fiebig.

"In the study we have actually discovered this kind of vortex field in a substance called lithium cobalt phosphate and employed laser-optics to determine its direction."

Borrowing from the term "ferromagnetism", the authors, who include Dutch scientist Bas Van Aken and Geneva-based physicists Hans Schmid and Jean-Pierre Rivera, have called the phenomenon "ferrotoroidicity".

This finding is described as "extremely interesting" from a fundamental research standpoint. But there could also be very practical consequences in terms of technological applications.

This is because magnetic vortices could be used to store information. When the atomic roundabout 'traffic' goes right, it could be made to stand for the binary number '0'. Going left, it could designate the '1'.

"We now store data by magnetically poling the surface coating of a hard disk, " explained Dr Fiebig.

"Today's data storage device contains many billions of polable zones, ordered in rows. To write information onto them or read from them you have to have magnetic fields."

He pointed out that this current technology has two problems. On the one hand, to produce the necessary fields there must be a flow of electricity for which electrical charge carriers are actuated, and this is a relatively slow process.

On the other hand, with ever greater densities of data, the danger is that the magnetic fields to be read can destroy the stored information.

The atomic roundabouts do not have these drawbacks. Here, information is also stored magnetically but, as Dr Fiebig pointed out, the "direction of rotation of the vortices can be changed by electrical fields".

Moreover, the reading process does not require a magnetic field that might overwrite the stored data by mistake. Another advantage is that no electricity has to flow to generate the electrical fields so, in principle, storage can run much faster.