NUS scientists have used ‘spin waves’ to switch magnetization at room temperature for more energy-efficient spin memory and logic devices.
This breakthrough of spin wave-based switching could enable more advanced energy-efficient chips, protecting mobile phones and computers from over-heating.
Traditional electronic chips suffer from substantial ‘Joule heat’, which occurs due to the flow of an electric current producing high temperatures.
This issue not only causes a large amount of power dissipation, but also hinders the chip’s processing speed and limits the number of chips that can be incorporated into appliances.
NUS professor Yang Hyunsoo and his team have now come up with a novel approach to sort out the joule heat problem in electronics.
Rather than adopting standard electron injection methods used in traditional electronics, Yang‘s team creatively used ‘spin waves’ to switch magnetisation.
Spin waves are propagating disturbances in the ordering of magnetic materials, and from the quasiparticle point of view, spin waves are known as ‘magnons’.
The team built a bilayer system consisting of an antiferromagnetic magnon transport channel and a topological insulator spin source.
In a world’s first, they then successfully demonstrated spin wave driven magnetization switching in the adjacent ferromagnetic layer with a high efficiency at room temperature.
According to the scientists, the new switching scheme avoids moving charges, ensuring less Joule heat and power dissipation for devices.
Yang contends that the same can be enhanced further so that the magnon torque becomes more energy efficient.
“We know that the electrical spin torque has opened the era for spintronic device applications such as magnetic random access memories (MRAMs),” notes first author Dr Wang Yi.
“We believe our report of the new magnon torque scheme for magnetisation switching is a game-changing idea in spintronics.”
“It will invigorate not only a new research area in magnonics, but also practical devices operated by magnons.”
Image and content: National University of Singapore