Ferromagnetism and magnetic edge effects in Fe-implanted WS₂ layers

Two-dimensional magnets are attracting great interest not only as a platform for new fundamental physics but also as a platform for applications in spintronic and optoelectronic devices [1]. Recent theoretical studies predicted the presence of ferromagnetism in transition metal dichalcogenide (TMD) [2]. One such TMD material is WS₂ which is shown to have weak ferromagnetic behavior [3]. Here, we experimentally demonstrate that the effect of Fe implantation in WS₂ has little to no effect on its ferromagnetism using nitrogen-vacancy (NV) diamond magnetometry [3]. We image the magnetic stray field produced by the WS₂ flakes (thickness = 2 – 50 nm), exfoliated from bulk substrates and transferred to the diamond side doped with NVs. We quantitatively analyze the spatially resolved induced magnetic field observations using COMSOL multiphysics magnetostatic simulation and find a good agreement with NV measurements. Distinct absorptive and dispersive-like transitions in the observed induced magnetic field along the edges of the WS₂ layers are attributed to the layer orientation with respect to the applied magnetic field along the NV axis [4]. This work opens the possibility of engineering the magnetic properties of WS₂. [1] C. Gong et al., Science 363, eaav4450 (2019). [2] R. Mishra, et al., Phys. Rev. B 88 144409 (2013) [3] X. Ding, et al., J. All. Comp. 772 (25), 740-744 (2019). [4] A. Laraoui, et al., Appl. Phys. Lett. 121, 060502 (2022). [4] Gas-Osoth, et al., under preparation