发表机构
Kansas State University（堪萨斯州立大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文研究一维偶极耦合纳米磁岛链的交替序静态畴壁，结合数值模拟与双子格理论，揭示了各向异性常数接近偶极耦合常数时畴壁宽度发散、外场致偶极倾斜及畴壁磁矩的拓扑特性。
AI 中文摘要
本文分析了一个具有偶极相互作用的一维 elongated 纳米尺度磁岛链模型，研究其具有逐点交替序的静态畴壁特性。非磁性衬底上的各向异性磁岛的长轴沿垂直于链方向（x方向）的横向（y方向）取向，且施加有横向外磁场。磁岛的磁偶极子$\boldsymbol{\u03bc}_n$被表示为固定长度$\u03bc$的宏自旋。最近邻（NN）偶极相互作用驱动横向交替序，支持双重简并、均匀、静态的y方向交替态，其中偶极子交替指向垂直于链的方向，形式为$\boldsymbol{\u03bc}_n = \u00b1(-1)^n \u03bc\boldsymbol{\u0177}$。在仅考虑最近邻相互作用的假设下，通过数值弛豫模拟找到了连接这两种交替态的畴壁，并采用双子格连续统理论对其进行分析。当单轴各向异性常数$K_1$从较大值下降至接近最近邻偶极耦合常数$D$时，畴壁宽度无限增大，且大x尺度下的连续统解与晶格数值解高度吻合。外磁场使偶极子向磁场方向发生极轻微的倾斜，倾斜程度在畴壁中心达到最大。研究发现，沿晶格扫描时，两个子格上的偶极子以相反方向旋转，导致畴壁具有较大的纵向磁矩。而小得多的横向磁矩则具有拓扑贡献，其大小取决于链长为奇数还是偶数。
英文摘要
A model for a one-dimensional chain of elongated nano-scale magnetic islands with dipole interactions is analyzed here for the properties of its static domain walls with site-by-site alternating order. The anisotropic magnetic islands on a nonmagnetic substrate have their longer axes oriented transverse ($y$-direction) to the chain direction ($x$-direction), in a transverse applied magnetic field. The islands' magnetic dipoles $\vecμ_n$ are represented as macrospins of fixed length $μ$. The nearest-neighbor (NN) dipole interactions drive transverse alternating order, allowing for doubly-degenerate, uniform, static, $y$-alternating states, where the dipoles alternately point transverse to the chain direction, as in $\vecμ_n = \pm(-1)^n μ\hat{y}$. Assuming only NN interactions, the domain walls connecting these two alternating states are found with numerical relaxation simulations and analyzed in a two-sublattice continuum theory. As the uniaxial anisotropy constant $K_1$ descends from larger values until it closely approaches the NN dipolar coupling constant $D$, the domain wall width grows indefinitely, and the large-$x$ continuum solutions closely approach the lattice numerical solutions. The applied field produces a very slight canting of the dipoles towards the field, maximum in the center of the domain wall. The dipoles on the two sublattices are found to rotate in {\em opposite senses} as one scans along the lattice, resulting in a large longitudinal magnetic moment of the domain wall. A much smaller transverse magnetic moment has a topological contribution that depends on whether the chain length is odd or even.
Comments26 pages, 13 figures
Journal refCondens. Matter 2026, 11(4), 34
