Switching performance comparison between conventional SOT and STT-SOT write schemes with effect of shape deformation

Abstract

We demonstrate the effect of shape deformation in spin-orbit torque magnetoresistive random access memory (SOT-MRAM) based on micromagnetic simulation by generating 1000 randomly deformed samples using the exponentially decaying autocorrelation function. The conventional in-plane magnetic field-assisted SOT write scheme and the recently proposed spin-transfer torque-spin-orbit torque (STT-SOT) hybrid write scheme were simulated and compared with the effect of the Gilbert damping constant (α) considered in the presence and the absence of the Dzyaloshinskii-Moriya interaction (DMI). We found that shape deformation of the MTJ can result in write failure or degradation of the switching time. To compensate the device-to-device performance variation induced by the shape deformation, the condition of high α and the presence of the DMI is desired for the magnetic field-assisted write scheme. The STT-SOT shows slight improvement in the switching performance for larger α and the presence of DMI while it retains 100% switching probability even with small α regardless of the DMI.