Comprehensive evaluation of torques in ultra-scaled MRAM devices

We present a generalization of the coupled spin-charge drift-diffusion formalism capable of accurately describing the spin and charge transport properties through magnetic tunnel junctions. Correction terms enable reproducing oscillations of the spin current in ferromagnets typical for quasi-ballistic transport. Our approach proves necessary to accurately capture an interplay between the interfacial Slonczewski and bulk-like Zhang-Li contributions to the torque in ultra-scaled MRAM devices. •Spin and charge drift-diffusion equations adapted to a magnetic tunnel junction.•Low value of dephasing length allows to reproduce interface torque absorption.•Reproduced MTJ sinusoidal angular dependence.•Correction terms enable reproducing ballistic torque oscillations.•Demonstrated interplay of bulk and interface torques in ultra-scaled MRAM cells.