Domain wall motion device for nonvolatile memory and logic - size dependence of device properties

Current-induced magnetic domain wall (DW)-motion device with a three- or four-terminal structure has considerable potential to trigger a profound transformation in memory and logic technologies. In this paper, we give an overview of DW-motion devices and describe their structure, operation method, and characteristics. Previous studies on the DW motion in nanowires with a Co/Ni multilayer are also reviewed. We also report on the experimental results regarding device properties, such as critical current, the time and energy required to displace the DW in the device, and retention properties with various device sizes down to 20 nm. The results reveal that writing properties are enhanced while sufficient retention properties are maintained as the device size is reduced, indicating that the DW-motion device has high scalability and compatibility with conventional semiconductor-based cells as well as ultralow power capability.