浙江大学王秀瑜博士团队取得一项新发现。他们利用纳米磁学中自旋-晶格耦合成功突破了尺寸依赖极限。相关论文发表在2025年1月6日出版的《美国化学会杂志》上。

磁性纳米材料的进一步小型化，本质上伴随着自旋有序畴的减少，从而导致尺寸依赖的磁性行为。因此，基于磁性纳米材料的纳米器件发展的一个长期障碍是，缺乏一种方法来突破纳米磁性的尺寸限制。

研究人员发现并利用了三维独立磁性纳米颗粒中的自旋-晶格耦合效应，首次突破了尺寸依赖的极限。所谓的自旋-晶格耦合涉及由晶格变形引起的，自旋构型和交换常数的变化。

研究人员将自旋-晶格耦合与g移联系起来，并采用二维磁共振成像来可视化g因子。随着晶格常数的减小（甚至约1%），g位移的正偏移量显著增加，表明自旋-晶格耦合更强，从而诱导从顺磁性到超顺磁性的转变，从而有效地突破了尺寸依赖的极限。

附：英文原文

Title: Beating the Size-Dependent Limit with Spin–Lattice Coupling in Nanomagnetism

Author: Mengmeng Li, Xiuyu Wang

Issue&Volume: January 6, 2025

Abstract: Further miniaturization of magnetic nanomaterials is intrinsically accompanied by a reduction in spin ordered domains, resulting in size-dependent magnetic behaviors. Consequently, a longstanding roadblock in the advancement of nanodevices based on magnetic nanomaterials is the absence of a method to beat the size-dependent limit in nanomagnetism. Here, we discover and exploit a spin–lattice coupling effect in three-dimensional freestanding magnetic nanoparticles to beat the size-dependent limit for the first time. The so-called spin–lattice coupling involves varying spin configuration and exchange constant of spin interactions induced by lattice deformations. We correlate spin–lattice coupling to g-shift and employ two-dimensional magnetic resonance imaging to visualize g-factor. As lattice constants decrease (even ～1%), positive offset of g-shift increases significantly, signaling stronger spin–lattice coupling, which induces a transition from paramagnetism to surperparamagnetism, thereby effectively beating the size-dependent limit.

DOI: 10.1021/jacs.4c12978

Source: https://pubs.acs.org/doi/abs/10.1021/jacs.4c12978