Work

Atomic-scale visualization of strain-tailored noncollinear spin textures in an antiferromagnetic ultrathin film

Year: 2025

Type: article

Abstract: Crystalline strain is typically considered as an effective approach to engineer low-dimensional antiferromagnets. However, a direct visualization of strained-tailored noncollinear spin textures in antiferromagnetic atomic layers has so far not been achieved. Here, we uncover a strain-induced transition from a three-dimensional noncollinear spin state in pseudomorphic Mn bilayer to a cycloidal spin spiral with a canted rotation plane in reconstructed Mn bilayer on the Ag(111) surface. These spin states are spatially imaged on the atomic scale by spin-polarized scanning tunneling microscopy revealing the correlation of atomic and magnetic structures. As demonstrated via first-principles electronic structure theory, the three-dimensional noncollinear spin state arises from the superposition of spin spiral and antiferromagnetic order due to higher-order exchange interactions. In reconstructed Mn bilayer, by contrast, the antiferromagnetic order is hindered by interlayer exchange coupling resulting in a pure spin spiral state. Our work highlights the complex interplay of atomic structure, intra- and interlayer exchange, as well as higher-order exchange interactions at antiferromagnetically coupled interfaces. Antiferromagnets have intrinsic robustness to external perturbations, and while useful for device miniaturization, it makes manipulation of antiferromagnetic spins and ordering challenging. Here, Chen, Drevelow and coauthors successfully image the strain induced transformation of noncollinear antiferromagnetic order in a manganese bilayer.

Source: Nature Communications

DOI: 10.1038/s41467-025-62465-8