Domain walls are used in magnetic-based memory and logic devices, such as racetrack memory. Such applications are promising in future high volume data storage and processing requirements by offering increased energy efficiency and data processing speed while maintaining the merit of traditional magnetic devices such as high storage density, low cost and high reliability. We have made logic device prototypes that encode information in the position of a DW in a ferromagnetic wire. The information is written using spin torque transfer from pulsed voltage clocks and read out using a magnetic tunnel junction. We showed that a single three-terminal device can perform AND and NAND operations, making it a universal gate. We demonstrate fanout of one device into two and propagation of inverting logic between three devices to form a shift register. This prototype demonstration shows that DW-logic devices have the necessary characteristics for future computing, including nonlinearity, gain, cascadability, room-temperature operation, and compatibility with field-effect transistors.
Diagram and SEM image of a domain wall logic device based on material with in-plane magnetic anisotropy.