Within linear continuum theory, no magnetic texture can propagate faster than the maximum group velocity of the spin waves. Here, by atomistic spin dynamics simulations and supported by analytical theory, we report that a strongly non-linear transient regime due to the appearance of additional magnetic textures results in the breaking of the Lorentz translational invariance. This dynamical regime is akin to domain wall Walker-breakdown in ferromagnets and involves the nucleation of an antiferromagnetic domain wall pair. While one of the nucleated domain walls is accelerated beyond the magnonic limit, the remaining pair remains static. Under large spin–orbit fields, a cascade of multiple generation and recombination of domain walls are obtained. This result may clarify recent experiments on current pulse induced shattering of large domain structures into small fragmented domains and the subsequent slow recreation of large-scale domains.

在线性连续体理论中，没有任何磁性纹理能够以自旋波的最大群速度传播得更快。在这里，通过原子自旋动力学模拟并得到分析理论的支持，我们报告说，由于出现了额外的磁织构而导致的强烈非线性瞬态状态导致了Lorentz平移不变性的破坏。这种动力学机制类似于铁磁体中的畴壁沃克击穿，并涉及反铁磁畴壁对的成核。尽管其中一个有核畴壁的加速度超过了镁磁极限，但其余一对仍保持静态。在大的自旋轨道场下，获得了畴壁的多重生成和重组的级联。