Discovery of room-temperature skyrmions brings spintronics closer
A diagram of skyrmions © Jonathan White/EPFL
A study in Japan (RIKEN Center for Emergent Matter Science) has identified the first material capable of hosting magnetic skyrmions at room temperature, which opens up the way for spintronic devices. EPFL’s Laboratory for Quantum Magnetism and the Paul Scherrer Institute contributed by proving the existence of skyrmions using neutron scattering.
Magnetic skyrmions are tiny, magnetic-spin vortices that can emerge in magnetic materials. Because of their nanometer size, skyrmions could be used to build extremely dense-memory devices, virtually ushering a new class of low-power-consumption devices called “spintronics”. However, skyrmions are not easy to control, and researchers have been trying to create stable skyrmions for years. A breakthrough study in Japan and Switzerland has now discovered a new class of materials that display stable skyrmions at room-temperature. The work is published in Nature Communications.
The RIKEN Center for Emergent Matter Science, engineered alloys of cobalt, zinc, and manganese materials whose structure was likely to host stable skyrmions. Using a technique called "Small-Angle Neutron Scattering", Henrik Rønnow’s Laboratory for Quantum Magnetism (EPFL) and Jonathan White from the Swiss Neutron Source (PSI) were able to prove that when a magnetic field was applied, these materials indeed displayed skyrmions, which means that skyrmions can be integrated into spintronics devices without complicated cooling systems.
The skyrmions in these materials were found to be chiral and stable. This is important because they can be manipulated to encode information, with the presence or absence of skyrmions representing bits in computer processes.
“We are quite excited about these results," says first author Yusuke Tokunaga. "They may answer the long-held expectation that we can find skyrmion-hosting systems in a variety of new materials”.
“These materials are topologically protected,” adds Henrik Rønnow. “That means that it would require a lot of energy to switch the spin directions, and that’s what would make them considerably more stable for memory storage.”
This work was carried out by RIKEN CEMS in collaboration with EPFL, the Paul Scherrer Institut, and the University of Tokyo.
Reference
Tokunaga Y, Yu XZ, White JS, Rønnow HM, Morikawa D, Taguchi Y, Tokura Y. A new class of chiral materials hosting magnetic skyrmions beyond room temperature. Nature Communications 02 July 2015. DOI: 10.1038/ncomms8638