Perpendicular magnetic anisotropy induced by antiferromagnetic FexMn1−x alloy films: Influence of antiferromagnetic spin structure and long-range ordering

Antiferromagnets show potential as materials for generating perpendicular magnetic anisotropy (PMA) in neighboring ferromagnetic (FM) thin films. In this study, we investigate the behaviors of PMA induction and the underlying mechanisms in a series of epitaxially grown face-centered-cubic-like FeₓMn_1-x/Co/Fe/Cu(001) antiferromagnetic (AFM)/FM films. Our research reveals that decreasing the Fe composition ratio enhances the long-range AFM ordering of FeₓMn_1-x films. When the Fe composition ratio is lower than approximately 0.3, the impact of the AFM FeₓMn_1-x films on inducing PMA in the adjacent FM layer shifts from enhancement to suppression, providing important clues to a transformation in the spin structures of AFM FeₓMn_1-x films from a FeMn-like three-dimensional quadratic structure to an Mn-like two-dimensional layered structure. Our findings elucidate the compositional effects of AFM FeₓMn_1-x films on inducing PMA in the adjacent FM layer, as well as their relationship with the AFM spin structure and long-range AFM ordering, thereby showing the potential of Fe0.4Mn0.6 ultrathin films as promising candidates for effectively generating PMA. Such insights are crucial for understanding the AFM spin configuration of FeₓMn_1-x alloy films and for furthering the control of PMA using AFM layers.