滑动磁转子阵列的能量景观与耗散

中文摘要 AI 辅助

磁耦合的阻尼转动自由度在相对滑动运动激发时会产生摩擦学损耗，将摩擦与磁矩动力学关联起来。我们通过研究一种新近提出的、简化的刚性磁转子阵列在公度磁衬底上滑动的模型，对这类磁摩擦进行分析研究。该阵列的转子可绕垂直于滑动方向的轴转动，并受微观轴摩擦阻尼，而衬底磁体具有固定的面内取向。该简化模型将该装置的集体转子动力学约化为一组耦合非线性微分方程，可在准静态 regime（ regime 译为“区域”）中通过对应的能量景观进行研究。我们发现，由层间距和时间构成的参数平面可划分为不同的 chamber（ chamber 译为“区域”），各区域内能量景观的结构保持不变。利用这些区域，我们确定了对应不同动力学状态的层间距区间，并重现了一种 regime 的出现，在该 regime 中，磁矩取向全局交替，同时表现出峰值耗散。此外，我们推导了阵列与衬底之间小间隙和大间隙 regime 下集体磁摩擦的主导非平凡阶。对于交替 regime，我们发现可通过追踪区域边界处从不稳定临界点到稳定临界点的能量跳跃来计算摩擦。这些结果为滑动转子阵列中观测到的动力学与耗散提供了分析基础。由于该简化模型是无尺度的，我们的结论可推广到广泛的微观和宏观长度尺度。

英文摘要

Magnetically coupled damped rotational degrees of freedom can give rise to tribological loss when excited by a relative sliding motion, linking friction to the dynamics of magnetic moments. We analytically investigate such magnetic friction by studying a recently introduced simplified model for a rigid magnetic rotor array sliding over a commensurate magnetic substrate. Here, the array rotors can rotate about an axis perpendicular to the sliding direction and are damped by microscopic shaft friction, while the substrate magnets have a fixed in-plane orientation. The simplified model reduces the collective rotor dynamics of this setup to a set of coupled nonlinear differential equations, which can be studied by the corresponding energy landscape in the quasi-static regime. We find that the parameter plane spanned by layer separation and time can be divided into distinct chambers, in which the structure of the energy landscape remains invariant. Using these chambers, we identify the layer separation intervals corresponding to different dynamical states and recover the emergence of a regime where the moment alignment alternates globally while exhibiting peak dissipation. Additionally, we derive the leading nontrivial orders of the collective magnetic friction in the regimes of small and large gaps between the array and the substrate. For the alternating regime, we find that friction can be computed by tracking energy jumps from unstable to stable critical points at the chamber boundaries. These results provide an analytical foundation for the observed dynamics and dissipation in sliding rotor arrays. Because the simplified model is scale-free, our conclusions transfer across a broad range of microscopic and macroscopic length scales.

发表机构

• University of Notre Dame（圣母大学）
• Universität Innsbruck（因斯布鲁克大学）

机构由 AI 辅助整理，请以论文原文为准。