UCLA researchers have developed a nanoscale magnetic component for memory chips in a step towards spintronics.
Spin-based electronics store information by using electrons' spin rather than their charge. Researchers are looking for a way to use both the spin and the orbital properties of electrons, also known as "spin-orbit torque".
Spintronics-based computer chips use magnetic materials for increased power efficiency. Existing spin-orbit torque devices, can only trigger a memory writing and computing processes by using an electric current to switch the polarity of an adjacent magnetic material. To complete the switch, an adjacent magnetic field needs to be generated in addition to the electric current.
The UCLA researchers came up with a new structure for the magnetic material to eliminate the need for an adjacent magnetic field. The researchers instead created an effective magnetic field by varying the angle of the structure by just a few atoms, creating a shape which is thicker on one end and sloping downward to a thinner edge on the other end.
Although the height difference between the two ends is only a few tenths of a nanometer — or a few billionths of a meter — over the length of each device, the new configuration generates significant additional spin-orbit torque, which could potentially use one-hundredth the amount of energy used by the chips in today's consumer electronics.
"This work will likely provide a powerful approach for engineering new nanoelectronic devices and systems," said Kang Wang, the Raytheon Professor of Electrical Engineering at the UCLA Henry Samueli School of Engineering and Applied Science and the study's principal investigator.
"In conjunction with related types of magnetic devices being studied by our team, it represents a tremendous opportunity to realize higher performance memory and logic for future instant-on and energy-efficient, green electronic systems."