Abstract

The motion of domain walls in chiral magnets with symmetry broken relative to spatial inversion is investigated theoretically. It was found experimentally that such walls, which are known as the Dzyaloshinskii domain walls [22], exhibit unique dynamic properties. For chiral ferromagnets and antiferromagnets, nonlinear regimes of the motion of such a wall with the velocity up to its critical value have been investigated. The dynamics of walls in antiferromagnets can be described analytically, while for ferromagnets, numerical analysis must be used. Simple approximate expressions derived for ferromagnets describe dynamic characteristics of walls to a high degree of accuracy in the entire domain of their existence. The dispersion relations (i.e., the dependences of the energy of a wall on its linear momentum) are determined. For ferromagnets with purely uniaxial anisotropy, the critical velocity of a wall is determined exclusively by the chiral interaction and vanishes in the absence of this interaction. For antiferromagnetic, the role of the chiral interaction is not so obvious: like in the standard models for antiferromagnets, the structure of a moving wall can be obtained with the help of the Lorentz transformation with a chosen speed equal to the velocity of magnons in the linear part of the spectrum; however, the dispersion relation is more complicated and cannot be described by Lorentz-invariant expressions.

中文翻译：

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手性磁铁中畴壁的动力学

摘要

理论上研究了相对于空间反转的对称性破缺的手性磁体中畴壁的运动。实验发现，这种被称为 Dzyaloshinskii 畴壁 [22] 的壁表现出独特的动态特性。对于手性铁磁体和反铁磁体，已经研究了这种壁在速度达到其临界值时运动的非线性机制。反铁磁体中壁的动力学可以通过分析来描述，而对于铁磁体，则必须使用数值分析。为铁磁体推导出的简单近似表达式在其存在的整个域中高度准确地描述了墙壁的动态特性。色散关系（即墙的能量与其线性动量的关系）被确定。对于具有纯单轴各向异性的铁磁体，壁的临界速度完全由手性相互作用决定，并且在没有这种相互作用时消失。对于反铁磁，手征相互作用的作用不是那么明显：就像在反铁磁的标准模型中一样，在洛伦兹变换的帮助下，移动壁的结构可以在选定的速度等于磁振子速度的情况下获得光谱的线性部分；然而，色散关系更复杂，不能用洛伦兹不变表达式来描述。就像在反铁磁体的标准模型中一样，可以在洛伦兹变换的帮助下获得移动壁的结构，选择的速度等于频谱线性部分中磁振子的速度；然而，色散关系更复杂，不能用洛伦兹不变表达式来描述。就像在反铁磁体的标准模型中一样，可以在洛伦兹变换的帮助下获得移动壁的结构，选择的速度等于频谱线性部分中磁振子的速度；然而，色散关系更复杂，不能用洛伦兹不变表达式来描述。