Technology for magnetic memory does not need magnetic fields

Vortex domain wall

The data storage technologies of the future may have to rely on a kind of twisted magnetic nanostructure, called " magnetic vortex ," which are magnetic walls that have magnetic moments in the form of swirling around (vortex domain wall).

This structure is the basis for making one-millionth magnetic disks. Understanding the characteristics of this type of structure is an important requirement for developing a new generation of magnetic data storage technology. This result has just been published in Nature Materials .

A group of scientists at Kyoto University (Japan) have found a way to control the magnetization of magnetic vortex without placing an external magnetic field on a magnetic disk. Instead, they inserted the disc from an electric current.

"We have achieved an important step while using electricity. An adequate current will resonate with the vortex and make it spin at high speed - long velocity can reach several hundred meters each. Second, this motion creates a strong magnetic field that counteracts the magnetization of the vortex structure itself and reverses its magnetization, "said Teruo ono (of the research group).

The current used is actually not the flow of electrons but a " spin stream " - the flow of spin movements. (A spin state can propagate in one line, many of that propagation will produce spin currents).

Images of vortex formations when controlling movement
(Nature Materials 6, 270, 2007).

Researchers around the world are racing to create electronic devices that use spintronics. Research by the Kyoto team opened up the ability to make simple magnetic discs that underlie the same spintronic devices as memory cells, where each bit of information is stored in the direction of the magnetic field of the vortex nucleus. This study also illustrates a way to write data into memory very effectively.

"The spillover effect allows us not to use large magnetic fields to control magnetic devices, which means we don't have to waste the time and design to maintain such large magnetic fields. , " said ono.