近日，清华大学宋成团队研究了手性反铁磁序的无场全开关。这一研究成果于2026年2月25日发表在《自然》杂志上。

手性反铁磁体具有八极有序并结合了反铁磁体与铁磁体的优势。尽管已开发出多种开关策略，但无场全开关仍属未知，这构成了其在内存技术中实际应用的重要障碍。

研究组制备了一个由Mn₃Sn(0001)底层和多晶Mn₃Sn顶层构成的同质结。多晶Mn₃Sn中存在的倾斜Kagomé几何结构将Mn₃Sn(0001)层的面外自旋极化分成了Kagomé平面外和平面内的分量，分别生成对称的（反铁磁体类型）和非对称的（铁磁体类型）驱动力。前者加速八极旋转，后者则决定开关手性。

无场全开关在一种非常规协议中实现，该协议整合了反铁磁体与铁磁体开关的优势，超越了传统需要垂直单轴各向异性的全开关框架。研究组实现了前所未有的开关效率，得益于八极有序的自旋扭矩特性带来的高效驱动力，以及平面各向异性导致的极低能量垒，克服了传统协议中的权衡。无场开关还展现出八极可编程手性和对外部磁场的鲁棒性等显著优势。

附：英文原文

Title: Field-free full switching of chiral antiferromagnetic order

Author: Zhou, Zhiyuan, Cao, Yanzhang, Pan, Zhuorui, Zhang, Yingying, Liang, Shixuan, Pan, Feng, Song, Cheng

Issue&Volume: 2026-02-25

Abstract: Chiral antiferromagnets1,2 host octupole order3,4 and combine the advantages of antiferromagnets and ferromagnets. Despite the development of numerous switching strategies5,6,7,8,9, the field-free full switching remains unknown, posing an important obstacle to their practical application in memory technology. Here we prepared a homo-junction constituted of Mn3Sn(0001) bottom layer and polycrystalline Mn3Sn top layer. The tilted Kagomé geometry in polycrystalline Mn3Sn divides the out-of-plane spin polarization from Mn3Sn(0001) layer10,11 into the out-of-Kagomé-plane and in-Kagomé-plane components, generating the symmetric (antiferromagnet-type) and asymmetric (ferromagnet-type) driving forces, respectively. The former accelerates octupole rotation, whereas the latter determines switching chirality. Field-free full switching is realized in the unconventional protocol that integrates the advantages of both antiferromagnetic and ferromagnetic switching. It goes beyond the conventional full-switching framework requiring perpendicular uniaxial anisotropy7,12. An unprecedented switching efficiency is achieved, with both current density and power consumption an order of magnitude lower than in previous configurations, by virtue of the highly efficient driving forces due to spin-torque characteristics of octupole order and the ultralow energy barrier arising from easy-plane anisotropy, overcoming their trade-off in conventional protocols. The zero-field switching also shows the advantages of octupole-programmable chirality and robustness to external magnetic field.

DOI: 10.1038/s41586-026-10175-6

Source: https://www.nature.com/articles/s41586-026-10175-6