Domain-wall-motion cell with perpendicular anisotropy wire and in-plane magnetic tunneling junctions

A wire with perpendicular magnetic anisotropy (PA) is suitable for domain-wall-motion (DWM) cells because its critical current is small. However, it is not easy to design a cell consisting of a high magnetoresistance (MR) ratio magnetic tunneling junction (MTJ) and a DWM using PA material alone. We propose a combination of a PA-DWM element and in-plane (IP) MTJ for detection. The structure can be designed in a way that reduces the write current by the use of a perpendicular layer, yet maintains a high MR ratio by the independent use of in-plane material stacks. We fabricated a cell and ran tests to determine its read and write properties. A critical write current of 700 μA and a MR ratio of 50 were achieved. These properties are almost the same as when a DWM wire and in-plane MTJ are fabricated separately, which means it is possible to design the two elements independently.