外观
论文arXiv 2610.1424719 天前
分割磁化提高铁磁胶体的稳定性极限
原文链接：Partitioning the magnetization raises the stability limit of ferromagnetic colloids（arXiv 2610.14247 · 发布日期：2026-10-09）
Partitioning the magnetization raises the stability limit of ferromagnetic colloids
针对永久偶极导致胶体不可逆结合的问题，提出将固定磁矩分割为内部单元，并在57个样品和三种几何中验证稳定性提升。
核心要点
- 永久偶极的近接触吸引随磁矩平方增长，限制强磁化胶体悬浮液稳定。
- 将固定磁矩M分成N个内部元素，保持远场相互作用和每种驱动力不变。
- 实验显示近场成对能量被抑制为1/N，稳定性按约M²/N边界塌缩。
- 液相磁力显微类比直接成像能量景观，弱场中快于等尺寸超顺磁珠。
验证范围与局限：验证范围为57个样品和三种几何，并包含弱场、远离磁源条件下的比较。
英文摘要 (Abstract)
Magnetic actuation scales with a particle's magnetic moment, yet practical colloidal suspensions remain superparamagnetic or weakly magnetized, a permanent dipole drives a near contact attraction growing as the square of the moment, binding particles irreversibly. Here we show that this constraint depends not only on how much magnetic material a particle carries, but on where it sits. Partitioning a fixed moment M into N internal elements leaves the far field interaction, and every actuation force, unchanged while suppressing the near-field pair energy by 1/N. As we show in our experiments across 57 samples and three geometries, stability collapses onto a single $\sim M^{2}/N$ boundary, raising the accessible dipolar energy scale nearly 150-fold. A liquid-phase analogue of magnetic force microscopy images the engineered energy landscape directly. The resulting colloids outrun size-matched superparamagnetic beads in weak fields far from a magnetic source, suggesting their applicability in hard to reach places. Together, these results open a new operating regime for colloidal manipulation, with impactful implications in microfluidics and drug delivery.
作者：Paramita Modak, Priyadharshini M, Ankur Jaiswar, Ambarish Ghosh
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