Stochastic Processes in Magnetization Reversal Involving Domain-Wall Motion in Magnetic Memory Elements

We show experimentally through single-shot time-resolved conductance measurements that magnetization reversal through domain-wall motion in sub-100-nm-diameter magnetic tunnel junctions is dominated by two distinct stochastic effects. The first involves the incubation delay related to domain-wall nucleation, while the second results from stochastic motion in the Walker regime. Micromagnetics simulations reveal several contributions to temporal pinning of the wall near the disk center, including vertical-Bloch line nucleation and wall precession. We show that a reproducible ballistic motion is recovered when the Bloch and Neel wall profiles become degenerate in energy in optimally sized disks, which enables quasideterministic motion.

Automated summary

In sub-100-nm-diameter magnetic tunnel junctions, magnetization reversal through domain-wall motion is shown to be dominated by two distinct stochastic effects: incubation delay related to domain-wall nucleation and stochastic motion in the Walker regime. Micromagnetics simulations reveal various factors contributing to temporal pinning of the wall near the disk center, such as vertical-Bloch line nucleation and wall precession. Reproducible ballistic motion is achieved when the Bloch and Neel wall profiles become degenerate in energy in optimally sized disks, enabling quasideterministic motion.