Surface magnetic switching in lower dimensional ferromagnetic films*

Ferromagnetic (FM) thin films have long been studied for their technological importance and are essential for magnetic storage devices. Recent work has studied the effects of transition metal dichalcogenides on FM films whose interfaces are a subject of great interest due to their outstanding electrical, magnetic, and optical properties. The addition of an optical layer to a FM material may allow us to externally tune the magnetic properties of the films using light. In this work, we aim to understand the reduced dimensionality effect on the magnetic switching and surface properties of Fe thin films. We studied the impact on the surface magnetic properties of Fe films grown on top of WS₂, using the magneto optical Kerr effect, magnetic force microscopy and vibrating sample magnetometry. To conduct our experiments, we used 50 nm and 5 nm Fe films grown on Si substrates, and Fe/WS₂ films grown on Si and MgO substrates. We found that the reduced dimensionality of the Fe thin film leads to a decrease in the coercive field (H_c). In the Fe/WS₂/Si sample, we observe no change in H_c compared to the reference Fe/Si film. In the Fe/WS₂/MgO sample, we observe a slight increase in H_ccompared to the reference film. The addition of the optical layer (WS₂) preserved the magnetic qualities of Fe, showing that it is possible for the two layers to coexist without degrading the FM properties of the film.