As the size of conventional transistors – as predicted by Moore’s Law – rapidly approaches the theoretical minimum, Cambridge University physicists say they’ve made a major step forward in spintronics – a possible successor to the transistor.
Spintronics exploits the electron’s tiny magnetic moment, or ‘spin’, instead of its charge, as at present. It offers potential for high-speed, high-density and low-power consumption.
The new research sheds light on how to make ‘spin’ more efficient.
One of the unique properties in spintronics is that spins can be transferred without the flow of electric charge currents. This is called ‘spin current’ and, unlike other ways of harnessing electrons, allows information to be transferred without generating heat in electric devices.
But one major remaining obstacle to a viable spin current technology is the difficulty of creating a volume of spin current large enough to support current and future electronic devices.
However, the Cambridge researchers say they’ve now cracked this problem. In order to create enhanced spin currents, the researchers used the collective motion of spins called spin waves (the wave property of spins). By bringing spin waves into interaction, they have demonstrated a new, more efficient way of generating spin current.
“You can find lots of different waves in nature, and one of the fascinating things is that waves often interact with each other,” says Dr Hidekazu Kurebayashi, from the University’sCavendish Laboratory.
“Likewise, there are a number of different interactions in spin waves. Our idea was to use such spin wave interactions for generating efficient spin currents.”
One of these, he says, called three-magnon splitting, generates spin current ten times more efficiently than using pre-interacting spin-waves.