标题： 反向单侧磁铁 显示英文标题

标题： Inverse Single-sided Magnet

摘要： 单侧磁铁仅在一侧产生磁场并在相对侧将其抵消，这一特性已在基础科学和工程中得到了多种应用。 在这里，我们提出了 {\it 逆} 单侧磁铁：一种非铁磁系统，可以选择性地吸引铁磁体的北极或南极，而对相反极不响应。 我们证明这种行为可以在微观八极磁体中出现。 为了说明这一点，我们分析了两个最小模型：一种是具有120度有序的共面磁结构，另一种是具有位点依赖各向异性的共线磁结构。 在这两种情况下，我们发现磁化响应相对于施加磁场的符号是非互易的。 值得注意的是，在后一个模型中，系统在一个磁场方向上表现出强磁化，在相反方向上则几乎没有响应。 这种对磁场的二极管式行为表明，逆单侧磁铁可能在控制磁干扰方面发挥关键作用，其潜在影响可与传统单侧磁铁相媲美。 显示英文摘要

摘要： A single-sided magnet generates a magnetic field on only one side while canceling it on the opposite side, a feature that has enabled diverse applications in both fundamental science and engineering. Here, we propose the {\it inverse} single-sided magnet: a non-ferromagnetic system that selectively attracts either the north or south pole of a ferromagnet while remaining unresponsive to the opposite pole. We demonstrate that such behavior can arise in microscopic octupolar magnets. To illustrate this, we analyze two minimal models: a coplanar magnetic structure with 120-degree ordering and a collinear magnetic structure with site-dependent anisotropy. In both cases, we find that the magnetization response is nonreciprocal with respect to the sign of the applied magnetic field. Notably, in the latter model, the system exhibits strong magnetization in one field direction and negligible response in the opposite direction. This diode-like behavior for magnetic fields suggests that inverse single-sided magnets could play a pivotal role in controlling magnetic interference, with potential impact comparable to conventional single-sided magnets.