Spin Injection in Thermally Assisted Magnetic Random Access Memory

摘要

An integrated thermal, micromagnetic, spin-momentum-transfer (SMT) model was developed to study the effect of SMT on the programming current required for thermally assisted magnetic random access memory (MRAM). The thermal portion of the model is used to compute Joule heating by the spin- polarized current, and it is based on a Crank-Nicolson inhomogeneous heat equation solver. The magnetic portion of the model is based on a micromagnetic Langevin dynamic Landau-Lifshitz-Gilbert solver including SMT torque. Simulations of thermally assisted magnetization reversal of 0.09 micrometers MRAM elements, heated by passing current through the barrier separating the pinned and free layers were performed. The free layer of the MRAM elements was switched using a magnetic field at fixed heating-SMT current bias. Results suggest that a spin- polarized heating current can be used to lower the programming current required to write thermally assisted MRAM if the direction of the heating current is properly synchronized with the reversal field.