29 August 2012
Spintronic speed limit breakthrough could enable next gen devices
US researchers have precisely measured a key parameter of electron interactions called non adiabatic spin torque that they say is essential to the development of next generation spintronic devices.
These devices use electron spin to write and read information, but scientists still need to understand how to manipulate spin as a reliable carrier of computer code.
The researchers from the US Department of Energy's Brookhaven National Laboratory say that the precision they achieved can guide the reading and writing of digital information, as well define the upper limit on processing speed.
"In the past, no one was able to measure the spin torque accurately enough for detailed comparisons of experiment and mathematical models," said Brookhaven Lab physicist Yimei Zhu. "By precisely imaging the spin orbits with a dedicated transmission electron microscope at Brookhaven, we advanced a truly fundamental understanding that has immediate implications for electronic devices."
The team applied a range of high frequency electric currents to a patterned film called permalloy, a material 50nm thick designed to contain any generated magnetic field. The trapped electron spins combine and spiral within the permalloy, building into an observable and testable phenomenon called a magnetic vortex core.
"By capturing images of this micrometre effect, we can deduce the precise value of the non adiabatic torque's contribution to the vortex, which plays out on the nanoscale," added Zhu.
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