Magnetic Domain Wall Energy Landscape Engineering in a Ferrimagnet.

Architectures based on a magnetic domain wall (DW) can store and process information at a high speed in a nonvolatile manner with ultra-low power consumption. Recently, transition-metal rare earth metal alloy-based ferrimagnets have attracted a considerable amount of attention for the ultrafast current-driven DW motion. However, the high-speed DW motion is subject to film inhomogeneity and device edge defects, causing challenges in controlling the DW motion and hindering practical application. In this work, we demonstrate a strategy for precisely engineering the DW energy landscape by locally modifying the compensation state in a ferrimagnet via ion irradiation by using the focused ion beam technique. A diode-like DW motion behavior is observed at the lateral junction interface, i.e., the boundary between irradiated and non-irradiated CoGd, enabling selective control over DW pinning and depinning at specific locations. Our work provides insight into the development of next-generation DW-based ferrimagnetic racetrack memory and logic devices.