Data travels down fiber-optic cables at frequencies of several terahertz. As soon as the data arrives on a PC or television, this speed must be throttled down to match the data processing speed of the device components; this speed currently is in the range of a few hundred gigahertz only. A technology was developed that can process the data up to 100 times faster and close the gap between the transport and processing speeds.

In general, data memory and storage rely on the use of ferromagnetic materials; however, these are associated with two drawbacks. First, the areal density and, thus, the storage capacity of these materials is restricted as they necessarily reach natural limits. This is because each bit of information is stored in a tiny bar magnet, each of which represents a 0 or a 1, depending on its alignment. But if these bar magnets are placed too close together, they begin to influence each other. The second problem is that there are also restrictions on the speeds with which data can be written to this type of storage medium. It is not possible to go faster than gigahertz rates; otherwise, it would require immense energy.

This is not the case with antiferromagnetic memories. They can be written to at a much higher density because in this type of memory, the bar magnets are always aligned alternately and have no effect on each other. This means they can store considerably more data and allow much faster writing speeds.

The initial research began by passing an electric current through the antiferromagnets, enabling alignment of the tiny storage units. A cable originally was used, but was a rather slow connection method. Instead of the cable, a short laser pulse is now used to induce an electric current. This current aligns the bar magnets, or spin moments. Instead of using cables, the new memory thus works wirelessly, and instead of requiring direct electric current, the effects are now generated using light.

For more information, contact Elena Hilp, Spin Phenomena Interdisciplinary Center (SPICE) Institute of Physics, at This email address is being protected from spambots. You need JavaScript enabled to view it.; +49 6131 39-21259.

Tech Briefs Magazine

This article first appeared in the September, 2018 issue of Tech Briefs Magazine.

Read more articles from this issue here.

Read more articles from the archives here.