Octupole-driven spin torque switching of antiferromagnetic tunnel junctions

Jaimin Kang; Mohammad Hamdi; Shun Kong Cheung; Lin-Ding Yuan; Mohamed Elekhtiar; Eric Matt; William Rogers; Andrea Meo; Peter G. Lim; M. S. Nicholas Tey; Anthony D'Addario; Shiva T. Konakanchi; Jordan Athas; Sevdenur Arpaci; Antoine Devincenti; Lei Wan; Sanjay C. Mehta; Nicholas Zogbi; Vinod K. Sangwan; Jean Anne C. Incorvia; Jennifer Fowlie; Pramey Upadhyaya; Mario Carpentieri; Vinayak P. Dravid; Mark C. Hersam; Jordan A. Katine; Gregory D. Fuchs; Giovanni Finocchio; Evgeny Y. Tsymbal; James M. Rondinelli; Pedram Khalili Amiri

arXiv · 2509.03026

Octupole-driven spin torque switching of antiferromagnetic tunnel junctions

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Abstract

Magnetic tunnel junctions (MTJs) 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 tunneling magnetoresistance (TMR) and spin-transfer torque (STT) effects, respectively. It was long assumed that neither of these effects could be sizeable in all-antiferromagnetic tunnel junctions (AATJs), since they exhibit no net magnetization. Recently, however, it was shown that AATJs based on chiral antiferromagnets do exhibit TMR due to their non-relativistic momentum-dependent spin polarization and cluster magnetic octupole moment (CMO), which are manifestations of their spin-split band structure. However, the reciprocal effect, i.e., the antiferromagnetic counterpart of STT, has been assumed non-existent due to the total electric current being spin-neutral. Here, we report nanoscale AATJs exhibiting this reciprocal effect, which we term octupole-driven spin-transfer torque (OTT). We demonstrate current-induced OTT switching of PtMn3|MgO|PtMn3 AATJs, exhibiting a TMR value of 363% at room temperature and switching current densities of the order of 10 MA/cm2. Our theoretical modeling 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.

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Jaimin Kang, Mohammad Hamdi, Shun Kong Cheung, Lin-Ding Yuan, Mohamed Elekhtiar, Eric Matt, William Rogers, Andrea Meo, Peter G. Lim, M. S. Nicholas Tey, Anthony D'Addario, Shiva T. Konakanchi, Jordan Athas, Sevdenur Arpaci, Antoine Devincenti, Lei Wan, Sanjay C. Mehta, Nicholas Zogbi, Vinod K. Sangwan, Jean Anne C. Incorvia, Jennifer Fowlie, Pramey Upadhyaya, Mario Carpentieri, Vinayak P. Dravid, Mark C. Hersam, Jordan A. Katine, Gregory D. Fuchs, Giovanni Finocchio, Evgeny Y. Tsymbal, James M. Rondinelli, Pedram Khalili Amiri. 2025-09-03. Octupole-driven spin torque switching of antiferromagnetic tunnel junctions. https://arxiv.org/abs/2509.03026

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