Examination of Magnetization Switching Behavior by Bi-Directional Read of Spin-Orbit-Torque MRAM

We propose a read-reliability model to construct a bi-directional stabilized spin-orbit-torque magnetoresistive random access memory (SOT-MRAM) structure. Since this model withstands magnetization switching with ten times the current compared with the conventional SOT-MRAM structure, it enables low power-consumption operation while maintaining read reliability. We used various materials with different axes of easy magnetization as ferromagnetic materials in the proposed model and confirmed that all the materials had disturbance reduction of ten times or more. The magnitude of the coercive force of the ferromagnetic material affected this reduction. We also evaluated the effectiveness of the proposed model regarding disturbance reduction for various device shapes and found there were differences in this effectiveness because the behavior of magnetization switching differs depending on the shape and that vortex magnetization affects the model. However, considering the array configuration of the proposed model, the number of memory cells was limited to about 1000; therefore, a more optimal configuration is required.