近日，美国西北大学Pedram Khalili Amiri团队报道了反铁磁隧道结的八极驱动自旋转移矩翻转。2026年10月21日，《自然》杂志发表了这一成果。

基于铁磁体的磁隧道结是自旋电子学的典型器件，在数据存储、计算和传感领域具有广泛应用。它们分别通过隧穿磁阻（TMR）和自旋转移矩效应，同时具备电学检测和调控磁序的机制。长期以来，人们认为在全反铁磁隧道结（AATJs）中这两种效应都不可能很大，因为全反铁磁隧道结没有净磁化。然而，最近研究表明，基于手性反铁磁体的AATJs确实表现出TMR，这归因于其非相对论性动量依赖自旋极化和团簇磁八极矩，而这些是其自旋分裂能带结构的表现。然而，互易效应，即自旋转移矩的反铁磁对应效应，一直被认为不存在，因为总电流是自旋中性的。

研究组报道了纳米尺度AATJs显示出这种互易效应，并将其称为八极驱动自旋转移矩（OTT）。他们展示了电流诱导的PtMn3|MgO|PtMn3AATJs的OTT翻转，室温下TMR值为363%，翻转电流密度约为10 MA cm-2。该理论建模通过跨AATJ的子晶格内和子晶格间自旋流之间的不平衡，等价地也通过每个PtMn3层的非零净团簇八极极化，解释了OTT的起源。这项工作为反铁磁自旋电子学建立了一个新的材料平台，并为深度微缩磁存储器和室温太赫兹技术提供了一条途径。

附：英文原文

Title: Octupole-driven spin torque switching of antiferromagnetic tunnel junctions

Author: Kang, Jaimin, Hamdi, Mohammad, Cheung, Shun Kong, Yuan, Lin-Ding, Elekhtiar, Mohamed, Matt, Eric, Rogers, William, Meo, Andrea, Lim, Peter G., Tey, M. S. Nicholas, DAddario, Anthony, Konakanchi, Shiva T., Athas, Jordan, Arpaci, Sevdenur, Devincenti, Antoine, Wan, Lei, Mehta, Sanjay C., Zogbi, Nicholas, Sangwan, Vinod K., Incorvia, Jean Anne C., Fowlie, Jennifer, Upadhyaya, Pramey, Carpentieri, Mario, Dravid, Vinayak P., Hersam, Mark C., Katine, Jordan A., Fuchs, Gregory D., Finocchio, Giovanni, Tsymbal, Evgeny Y., Rondinelli, James M., Khalili Amiri, Pedram

Issue&Volume: 2026-10-21

Abstract: Magnetic tunnel junctions based on ferromagnets are canonical devices in spintronics, with wide-ranging applications in data storage, computing and sensing. They simultaneously exhibit mechanisms for electrical detection and control of magnetic order through the tunnelling magnetoresistance (TMR)1,2,3,4,5 and spin-transfer torque6,7,8,9 effects, respectively. It was long assumed that neither of these effects could be sizeable in all-antiferromagnetic tunnel junctions (AATJs), considering that they have no net magnetization. However, it was recently shown that AATJs based on chiral antiferromagnets do exhibit TMR due to their non-relativistic momentum-dependent spin polarization and cluster magnetic octupole moment, which are manifestations of their spin–split band structure10,11,12,13. However, the reciprocal effect, that is, the antiferromagnetic counterpart of spin–transfer torque, has been assumed non-existent due to the total electric current being spin-neutral. Here we report nanoscale AATJs that display this reciprocal effect, which we term octupole-driven spin-transfer torque (OTT). We demonstrate current-induced OTT switching of PtMn3|MgO|PtMn3 AATJs, with a TMR value of 363% at room temperature and switching current densities of the order of 10MAcm–2. Our theoretical modelling explains the origin of OTT in terms of the imbalance between intra- and inter-sublattice spin currents across the AATJ, and, equivalently, in terms of the non-zero net cluster octupole polarization of each PtMn3 layer. This work establishes a new materials platform for antiferromagnetic spintronics and provides a pathway towards deeply scaled magnetic memory and room-temperature terahertz technologies.

DOI: 10.1038/s41586-026-11172-5

Source: https://www.nature.com/articles/s41586-026-11172-5