Gu Kai, Zhang Xiaoqian, Liu Xiangjie, Guo Xinlei, Wu Zhenqi, Wang Shuo, Song Qinxin, Wang Wei, Wei Lujun, Liu Ping, Ma Jingrui, Xu Yongbing, Niu Wei, Pu Yong
New Energy Technology Engineering Laboratory of Jiangsu Province & School of Science, Nanjing University of Posts and Telecommunications, Nanjing, 210023, China.
Key Laboratory of Quantum Materials and Devices of Ministry of Education, School of Physics, Southeast University, Nanjing, 211189, China.
Adv Sci (Weinh). 2024 May;11(17):e2307034. doi: 10.1002/advs.202307034. Epub 2024 Feb 14.
Exchange bias is extensively studied and widely utilized in spintronic devices, such as spin valves and magnetic tunnel junctions. 2D van der Waals (vdW) magnets, with high-quality interfaces in heterostructures, provide an excellent platform for investigating the exchange bias effect. To date, intrinsic modulation of exchange bias, for instance, via precise manipulation of the magnetic phases of the antiferromagnetic layer, is yet to be fully reached, owing partly to the large exchange fields of traditional bulk antiferromagnets. Herein, motivated by the low-field spin-flop transition of a 2D antiferromagnet, CrPS, exchange bias is explored by modulating the antiferromagnetic spin-flop phase transition in all-vdW magnetic heterostructures. The results demonstrate that undergoing the spin-flop transition during the field cooling process, the A-type antiferromagnetic ground state of CrPS turns into a canted antiferromagnetic one, therefore, it reduces the interfacial magnetic coupling and suppresses the exchange bias. Via conducting different cooling fields, one can select the exchange bias effect switching among the "ON", "depressed", and "OFF" states determined by the spin flop of CrPS. This work provides an approach to intrinsically modulate the exchange bias in all-vdW heterostructures and paves new avenues to design and manipulate 2D spintronic devices.
交换偏置在自旋电子器件中得到了广泛研究和应用，如自旋阀和磁性隧道结。二维范德华（vdW）磁体在异质结构中具有高质量的界面，为研究交换偏置效应提供了一个绝佳的平台。迄今为止，由于传统体反铁磁体的交换场较大，交换偏置的本征调制，例如通过精确操纵反铁磁层的磁相，尚未完全实现。在此，受二维反铁磁体CrPS的低场自旋翻转转变的启发，通过调制全vdW磁性异质结构中的反铁磁自旋翻转相变来探索交换偏置。结果表明，在场冷却过程中经历自旋翻转转变时，CrPS的A型反铁磁基态转变为倾斜反铁磁基态，因此，它降低了界面磁耦合并抑制了交换偏置。通过施加不同的冷却场，可以选择由CrPS的自旋翻转决定的“开”、“抑制”和“关”状态之间的交换偏置效应切换。这项工作提供了一种在全vdW异质结构中本征调制交换偏置的方法，并为设计和操纵二维自旋电子器件开辟了新途径。
