Simulation of Advanced MRAM Devices for sub-ns Switching

Abstract

This work explores pathways to achieve reliable sub-ns switching for Spin-Transfer Torque (STT) and Spin- Orbit Torque (SOT) MRAM devices by employing a coupled spin and charge drift-diffusion and micromagnetics simulation framework utilizing the Landau-Lifshitz-Gilbert (LLG) equation. We consider several vital mechanisms of spin current generation, such as spin current polarization in ferromagnets (FMs), the spin Hall effect (SHE) in heavy metals (HMs), the Rashba-Edelstein effect (REE) at HM/FM interfaces, the magnetic SHE (MSHE) in noncollinear anti-ferromagnets (NC-AFMs), and the anomalous Hall effect (AHE) in FMs. We employ boundary conditions based on quantum mechanical scattering from a magnetic exchange and Rashba SOC potential at the HM/FM interfaces. We also account for all critical effects in the LLG equation, such as the interfacial Dzyaloshinskii-Moriya interaction (DMI), the demag-netizing field, perpendicular magnetic anisotropy, and interlayer exchange coupling (IEC).