3D racetrack memory is expected to be the next-generation storage-class non-volatile memory, because it does not require a stair-case structure as in the case of 3D NAND flash memory. One of the major challenge in 3D racetrack memory is how to suppress shift error of magnetic domain walls due to variation in domain wall driving current density, pulse width, as well as domain wall velocity. While there are several techniques to suppress shift error in 2D racetrack memory such as local doping, local alloying, notching, and shaping of the racetrack, etc…such techniques are difficult to implement in a 3D structure.
In this work, we propose a new technique to suppress magnetic domain wall shift error that can be easily implemented in 3D, utilizing the spatially modulated perpendicular magnetic anisotropy (PMA) of magnetic nanowires that are induced by neighboring oxide layers.