Scientists generate first direct short-wavelength spin waves

DRESDEN, Germany, July 19 (UPI) -- Computers and smart technologies are approaching a size limit. Components can't get much smaller than they already are without easily overheating.

"One major problem with current technologies, is the heat which is generated when data are transmitted with the aid of electric currents," Sebastian Wintz, a scientist with the HZDR Institute of Ion Beam Physics and Materials Research, said in a news release. "We need a new concept."

If the trend of miniaturization is to continue, researchers say, engineers must find a substitute for electric currents. Scientists at Helmholtz-Zentrum Dresden-Rossendorf, a German research laboratory, may have already found a one.

Recently, researchers directly generated magnetic spin waves with extremely short wavelengths -- a first.

Currently, data processing is carried out by electric currents. Data-carrying charged particles are pushed across nanowires squeezed together on tiny computer chip. These particles create a lot of heat as they move. If electron-carrying nanowires get too close, heat fails to dissipate and the system fails.

Magnetic spin waves don't move particles but impart them with a magnetic moment. A change in spin rate can trigger a chain reaction among a series of ferromagnetic particles, propelling information across the surface of a tiny interface.

Currently, magnetic spin waves with extremely short wavelengths are generated via small metal antennae with a high-frequency alternating current. Until now, researchers haven't been able to create an antenna small enough to be used in computer processing.

Scientists developed a new way to generate the spin waves by creating a magnetic vortex in a small ferromagnetic disk. An alternating current supplied to the center of the disk creates and propels a magnetic spin wave.

To lower the wavelength of the spin wave further, researchers sandwiched a thin, non-magnetic layer with two of the disks. Due to antiferromagnetic coupling, the disks' two vortexes attempt to move in opposite direction. Their opposition ensures the emitted spin wave features a shortened wavelength.

"Only in this way do we arrive at a result which is relevant for information technology," Wintz said.

Researchers also found that the frequency of the alternating current can be manipulated to further augment the spin wave's wavelength.

Researchers shared their finding in a new paper, published this week in the journal Nature Nanotechnology.