Researchers generate ultra-short spin waves in an astoundingly simple material

Due to its potential to make computers faster and smartphones more efficient, spintronics is considered a promising concept for the future of electronics. In a collaboration including the Max Planck Institute for Intelligent Systems (MPI-IS) and the Helmholtz-Zentrum Dresden-Rossendorf (HZDR), a team of researchers has now successfully generated so-called spin waves much more easily and efficiently than was previously deemed possible. The researchers are presenting their results in the journal Physical Review Letters.

Modern computer chips are based on transporting electric charges. Each processing event causes an electron current to flow in an electronic component. These electrons encounter resistance, which generates undesired heat. The smaller the structures on a chip, the more difficult it is to dissipate the heat. This charge-based architecture is also partially the reason why the processors' clock rates have not seen any significant increases in years. The steady development curve of chip performance and speed is now flattening. "Existing concepts are reaching their limits," explains Dr. Sebastian Wintz from the Institute of Ion Beam Physics and Materials Research at HZDR. "This is why we are working on a new strategy, the spin waves."

This approach no longer involves transporting charges, but only transfers the electrons' intrinsic angular momentum (spin) in a magnetic material. The electrons themselves remain stationary, while only their spins change. Since the spins of neighboring electrons sense each other, a change in one spin can travel to its neighbors. The result is a magnetic signal running through the material like a wave—a spin wave. The advantage of spin-powered components is that they would generate very little heat, which means they might use significantly less energy—and this is of great interest for mobile devices such as smartphones. It may also be possible to further miniaturize components for certain applications because spin waves have far shorter wavelengths than comparable electromagnetic signals, for instance in mobile communication. This means we could fit more circuits onto a chip than we can today.