thin films*

Antiferromagnetic (AFM) materials are potential candidates for future spintronic applications owing to their ultrafast spin dynamics. AFM spintronics devices require high-quality thin films with controlled spin orientations. Here, we report the epitaxial growth of the (110)-oriented FeF₂ thin films, an AFM material, on MgF₂(110) substrate using molecular beam epitaxy. The structure of the FeF₂(110) thin film is characterized by both ex-situ X-ray diffraction (XRD) and in-situ reflection high energy electron diffraction (RHEED) studies. The uniaxial AFM spin configuration of FeF₂(110) films is further confirmed by the exchange bias effect in both FeF₂/Co and FeF₂/Ni bilayers. A clear exchange bias is observed when an external magnetic field (H_FC) is applied along the [001] direction while absent when the H_FC is along the [1-10] direction. The blocking temperature of a 50 nm FeF₂(110) film is ~80K, which is close to the Néel temperature of bulk FeF₂ (78K). Our epitaxial FeF₂(110) thin films will open up a promising direction for exploring AFM spintronic devices.