Domain-wall (DW) motion is a crucial process involved in magnetization reversal, be it under a magnetic field or spin-polarized current stimulus. In most cases the DW speed does not exceed $\sim 100\mathrm{m}\text{/}\mathrm{s}$ and collapses above a given threshold of the stimulus, an effect known as Walker breakdown. A few specific material properties have been identified to delay the breakdown of speed by increasing the energy barrier preventing internal precession. We show that in a three-dimensional nanomagnetic system, here with vortex-state domains in nanowires, the topology of the magnetization distribution may intrinsically and robustly delay the Walker breakdown due to an exchange-spring effect. However, in contrast to cases in lower dimension, the motion remains steady state. In addition, curvature induces a major nonreciprocal effect, delaying or not the Walker breakdown depending on the sequence of chiralities of the azimuthal domains on both sides of the DW, independent of its direction of motion.

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• Domain wall motion
• Exchange bias
• Magnetic domains
• Magnetic vortices
• Magnetization dynamics
• Micromagnetism
• 3-dimensional systems