Bonding Character and Magnetism at the Interface Between Fe and MoS2 Nanosheets

In order to enable the use of the prototypical 2D-layered MoS2 for spintronics, its integration with ferromagnetic layers is mandatory. By employing interface-sensitive 57Fe conversion electron Mössbauer spectroscopy (CEMS), hard X-ray photoelectron spectroscopy (HAXPES), and transmission electron microscopy (TEM), the chemical, structural, and magnetic properties of the Fe/2D-MoS2 interface are investigated. CEMS shows that out of the first 1 nm of Fe in direct contact with 2D-MoS2, about half of the Fe atoms keeps the un-perturbed Fe local environment, partly in regions where the original 2D-layered structure of MoS2 is preserved as shown by TEM. The remaining reacting Fe atoms exclusively bond with Mo, with the majority of them being characterized by a ferromagnetic environment and the rest coordinating in a paramagnetic Fe-Mo configuration. The preferential Fe bonding with Mo is corroborated by HAXPES analysis. The results provide detailed insight into the link between the bonding configuration and the interfacial magnetism at the Fe/2D-MoS2 heterojunction.