Electrical mutual switching in a noncollinear-antiferromagnetic–ferromagnetic heterostructure
Ju-Young Yoon, Yutaro Takeuchi, Ryota Takechi, Jiahao Han, Tomohiro Uchimura, Yuta Yamane, Shun Kanai, Jun’ichi Ieda, Hideo Ohno, Shunsuke Fukami
Abstract
Spin-orbit torque (SOT) provides a promising mechanism for electrically encoding information in magnetic states. Unlike existing schemes, where the SOT is passively determined by the material and device structures, an active manipulation of the intrinsic SOT polarity would allow for flexibly programmable SOT devices. Achieving this requires electrical control of the current-induced spin polarization of the spin source. Here we demonstrate a proof-of-concept current-programmed SOT device. Using a noncollinear-antiferromagnetic/nonmagnetic/ferromagnetic Mn3Sn/Mo/CoFeB heterostructure at zero magnetic field, we show current-induced switching in the CoFeB layer due to the spin current polarized by the magnetic structure of the Mn3Sn; by properly tuning the driving current, the spin current from the CoFeB further reverses the magnetic orientation of the Mn3Sn, which determines the polarity of the subsequent switching of the CoFeB. This scheme of mutual switching can be achieved in a spin-valve-like simple protocol because each magnetic layer serves as a reversible spin source and target magnetic electrode. It yields intriguing proof-of-concept functionalities for unconventional logic and neuromorphic computing. Spin-orbit torque can drive switching in ferromagnets, and therefore can be used for the electrical writing of magnetic bits. Here, Yoon et al. take this essential idea a step further, demonstrating mutual switching, where a ferromagnet can drive switching in an antiferromagnet, switching the sign of the spin-orbit torque itself.