Ferrimagnets speed up racetrack memories
September 24, 2018
Spintronics devices, which exploit the spin of an electron as well as its charge, could be ideal for use in high-density data storage devices and for next generation information processing. One promising technology involves using magnetic solitons, such as nanoscale domain walls and magnetic skyrmions, which can function as mobile bits, to encode information, and then moving these bits using a current in devices known as racetracks. The main challenges here are to make smaller bits and then efficiently move these at high speeds. Until now, researchers mainly focused on ferromagnetic materials to make such bits, but these unfortunately have their limitations for when it comes to how small they can be made and the speed at which they can be moved. Material scientists and physicists in the US and Germany say they have now found a way to overcome this problem by using ferrimagnets instead. This new class of materials allow for order-of-magnitude improvements in speed and size and means that the technology might now be brought to market in a reasonably short timeframe.
“We have succeeded in driving domain wall motion with a speed of 1.3 km/s in ferrimagnetic Pt/Gd44Co56/TaOxfilms using an applied current,” says Geoffrey Beach of the Massachusetts Institute of Technology (MIT), who led this research effort. “We have also found that the material hosts room-temperature-stable skyrmions as small as 10 nm in size.”