Wang Tianye, Li Qian, Yang Mengmeng, Sun Yu, N'Diaye Alpha T, Klewe Christoph, Scholl Andreas, Chen Xianzhe, Huang Xiaoxi, Zhang Hongrui, Yang Santai, Lee Ji-Eun, Balakrishnan Dhanvanth, Zhang Xixiang, Hwang Chanyong, Shafer Padraic C, Crommie Michael F, Ramesh Ramamoorthy, Qiu Zi Q
Department of Physics, University of California, Berkeley, CA, 94720, USA.
Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.
Adv Mater. 2025 Aug 1:e04700. doi: 10.1002/adma.202504700.
Atomically flat surfaces of van der Waals (vdW) materials pave an avenue for addressing a long-standing fundamental issue of how a compensated antiferromagnet (AFM) surface frustrates a ferromagnetic (FM) overlayer in FM/AFM heterostructures. We investigate FeGeTe/NiPS vdW heterostructures by characterizing AFM and FM spins separately. We find that in-plane zig-zag AFM NiPS develops three equivalent AFM domains, which are robust against external magnetic field and magnetic coupling with FeGeTe. Moreover, evidence is provided of in-plane-AFM-induced perpendicular magnetic anisotropy (PMA) in adjacent FeGeTe, and an unconventional out-of-plane surface spin canting state with the FeGeTe spins spatially turn from out-of-plane direction near the interface to in-plane direction away from the interface in FeGeTe/NiPS. The out-of-plane surface spin canting is a unique property of spin frustration in vdW magnetic heterostructures.
范德华（vdW）材料的原子级平整表面为解决一个长期存在的基本问题开辟了一条途径，即补偿反铁磁体（AFM）表面如何在铁磁（FM）/反铁磁异质结构中使铁磁覆盖层受挫。我们通过分别表征反铁磁和铁磁自旋来研究FeGeTe/NiPS范德华异质结构。我们发现，面内之字形反铁磁体NiPS形成了三个等效的反铁磁畴，它们对外部磁场和与FeGeTe的磁耦合具有鲁棒性。此外，还提供了证据表明相邻FeGeTe中存在面内反铁磁诱导的垂直磁各向异性（PMA），以及一种非常规的面外表面自旋倾斜状态，在FeGeTe/NiPS中，FeGeTe自旋在空间上从界面附近的面外方向转向远离界面的面内方向。面外表面自旋倾斜是范德华磁性异质结构中自旋受挫的独特性质。
